iRhythm Holdings, Inc. (IRTC) Business

ITEM 1: BUSINESS

Company Background

iRhythm is a leading digital healthcare company that creates trusted solutions that detect, predict, and prevent disease. Our principal business is the design, development, and commercialization of device-based technology to provide ambulatory cardiac monitoring services that we believe allow clinicians to diagnose certain arrhythmias quicker and with greater efficiency than other services that rely on traditional technology.

Each iRhythm product offering combines a wire-free, patch-based, 14-day wearable biosensor (United States Food and Drug Administration (“FDA”)-cleared, Conformité Européenne (“CE”)-marked and Japan Pharmaceuticals and Medical Devices Agency ("PMDA")-approved, as applicable) that continuously records electrocardiogram ("ECG") data with a proprietary cloud-based data analytic software (also FDA-cleared, CE-marked and Japan PMDA-approved, as applicable) (such biosensor and software together, an "iRhythm ACM System") to help physicians monitor patients and diagnose arrhythmias.

Since first receiving clearance from FDA for our technology in 2009, we have supported physician and patient use of this technology and provided ambulatory cardiac monitoring ("ACM") services from our Medicare-enrolled independent diagnostic testing facilities (“IDTFs”) with our qualified technicians. We have provided ambulatory cardiac monitoring services, including long-term continuous monitoring (“LTCM”) services ("LTCM Services"), short-term continuous monitoring, and mobile cardiac telemetry (“MCT”) monitoring services ("MCT Services" and collectively, the “iRhythm Services”), using the iRhythm ACM System. LTCM services and MCT Services are medical procedures typically ordered by physicians for patients not suspected of having life-threatening arrhythmias, but who are suspected of having infrequent, difficult-to-detect, or asymptomatic arrhythmias. Since receiving FDA clearance, we have provided iRhythm Services via more than twelve million patient reports and have collected almost three billion hours of curated heartbeat data.

iRhythm Technologies was incorporated in the state of Delaware in September 2006 and its successor registrant iRhythm Holdings was incorporated in the state of Delaware in December 2025. Our principal executive offices are located at 699 8th Street, Suite 600, San Francisco, California 94103, and our telephone number is (415) 632-5700. Our common stock is listed on The Nasdaq Global Select Market under the symbol “IRTC,” and we employ approximately 2,400 regular full-time employees as of December 31, 2025.

Our website address is https://www.irhythmtech.com, and our investor relations website is located at https://investors.irhythmtech.com. Our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and amendments to reports filed pursuant to Sections 13(a) and 15(d) of the Exchange Act are available free of charge on our investor relations website as soon as reasonably practicable after we file such material with the SEC.

iRhythm investors and others should note that we announce material information to the public about our company, products, and services, and other issues through a variety of means – including via our website, our investor relations website, press releases, SEC filings, and public conference calls – to achieve broad, non-exclusionary distribution of information to the public and to comply with our disclosure obligations under Regulation FD. We encourage our investors and others to review the information we make public in these locations as such information could be deemed material. Please note that this information may be updated from time to time.

Cardiac Arrhythmias and the Ambulatory Cardiac Monitoring Market

Every year, millions of patients experience symptoms potentially associated with cardiac arrhythmias, a condition in which the electrical impulses that coordinate heartbeats do not occur properly, causing the heart to beat too quickly, too slowly, or irregularly. There are many different types of arrhythmias which are typically categorized based on where in the heart they originate - in either the atria or ventricles - and their speed - tachycardia for fast rhythms, bradycardia for slow rhythms. The causes of arrhythmias are diverse, and they can be triggered by conditions such as heart disease, high blood pressure, electrolyte imbalances, drug use, or stress. Some arrhythmias may not show symptoms, while others may lead to dizziness, shortness of breath, fainting, or chest pain. The Centers for Medicare and Medicaid Services' ("CMS") Hierarchical Condition Categories (HCC 96) defines actionable arrhythmias as abnormal heart rhythms detected via monitoring that require clinical intervention, such as medication adjustment, anticoagulation, catheter ablation, or device implantation.

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Cardiac arrhythmias affect approximately 1.5% to 5% of the global population, with atrial fibrillation ("Afib") being the most common. Afib causes the upper chambers of the heart to beat irregularly and blood not to flow properly to the lower chambers of the heart. It is estimated that more than 50 million patients worldwide have Afib with at least one-third of these patients presenting as asymptomatic at the time of their diagnosis. This condition contributes to an estimated 350,000 deaths globally each year. In the United States, the prevalence of Afib is estimated to be approximately 4.5% of people, or approximately 10.6 million adults diagnosed with Afib in 2019, and more than 450,000 hospitalizations occur each year in the United States because of Afib. Because Afib is more common among people over the age of 60, these numbers are expected to increase as the U.S. population ages. In Europe, the prevalence of arrhythmias is also expected to continue to rise with Afib affecting approximately 12.9 million people in the EU in 2021, and projections indicating the number could double by 2050–2060.

Atrial Fibrillation and Stroke

Early detection of heart rhythm disorders, such as Afib and other clinically relevant arrhythmias, supports appropriate medical intervention and can help avoid more serious downstream medical events, including stroke. In 2021, it was estimated that the age-adjusted US stroke death rate as an underlying cause of death was approximately 41.1 per 100,000, and there were approximately 7.4 million deaths attributable to stroke worldwide. Afib is the leading risk factor for stroke because Afib can cause blood to collect in the heart and potentially form a clot, which can then travel to the brain possibly resulting in an ischemic stroke. While individuals with Afib are approximately five times more likely to suffer a stroke, the American Stroke Association (“ASA”) estimated in 2022 that up to 80% of second clot-related strokes may be preventable. According to the American Heart Association ("AHA"), stroke costs the United States an estimated $34.5 billion each year in healthcare costs and lost productivity and is a leading cause of serious long-term disability. Between 15% and 20% of people who have strokes also have Afib.

We believe early detection of Afib is critical to optimizing patient care, delivering earlier treatment to help avoid further adverse clinical events, managing symptoms caused by Afib, and reducing the total public health burden of treating stroke. The AHA and ASA have published treatment guidelines for patients diagnosed with Afib to manage heart rhythm and rate and to support stroke prevention. These early treatments include medications such as oral anticoagulants, treatment with anti-arrhythmic drugs, and interventions such as cardiac ablation therapy to help control heart rhythm and rate.

Afib burden, or the amount of time a patient spends in Afib during the period of time the patient is wearing a heart monitor, has been identified in the clinical community as a clinically relevant measure for helping to determine appropriate and effective therapeutic interventions to manage patients with Afib and for assessing stroke risk. We believe the calculated Afib burden is only as good as the data available for analysis during the monitoring period. Since the most common type of Afib occurs intermittently, we believe that long-term continuous monitoring with patch-based technology, such as with our monitor technology that is part of our iRhythm ACM Systems, can more accurately measure Afib burden as it captures the patient’s heartbeat data is captured continuously through the wear period.

Ambulatory Cardiac Monitoring Overview

The ACM market is well-established in the United States with an estimated 6.9 million diagnostic tests performed in 2025 with meaningful expansion anticipated in the coming years due to an aging population, a rising number of heart-related disorders globally, and broader acceptance of innovative medical technologies. Traditional ambulatory cardiac monitoring devices used by physicians for diagnosing patients with suspected arrhythmias – such as traditional, 24-to-48-hour Holter and cardiac event monitors – are constrained by short-term monitoring times, non-continuous data collection and reporting, cumbersome equipment, and/or lower patient compliance. For example, patients often remove traditional monitors when sleeping, showering, or exercising, which can lead to a failure to capture critical data and result in incomplete diagnoses and repeat testing, which in turn can result in suboptimal patient care and higher costs to the health system.

Arrhythmia symptoms are generally monitored either in a physician’s office or healthcare facility, or with the ambulatory cardiac monitoring services. Typically, physicians will administer a resting ECG test in their offices to record and analyze the electrical impulses of patients’ hearts. If physicians determine that patients require monitoring for a longer wear period to generate a diagnosis, they have historically prescribed an ambulatory cardiac monitoring device such as a traditional Holter monitor, which is a non-invasive, battery-powered device that typically records data continuously for 24 to 48 hours. For longer term (i.e., up to 30 days) event driven monitoring, physicians may prescribe ambulatory cardiac event monitoring services, including MCT services, which record ECG data upon auto-detection (i.e., asymptomatic events) and/or patient activation (i.e., symptomatic events) and may transmit such data wirelessly to a monitoring center like an IDTF. Physicians may also prescribe implantable loop

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recorders, which are implanted underneath the patient’s skin in a minimally invasive, hospital-based procedure and record ECG data similar to cardiac event monitors but are intended for monitoring up to 3 years.

If the diagnosis is not definitive following the first monitoring period, physicians may prescribe a repeat traditional, 24-to-48-hour Holter monitoring test or, alternatively, event monitoring services, MCT, or implantable loop recorders. Physicians use frequency and acuity of symptoms to determine which monitoring device to prescribe. Some physicians own their own ambulatory cardiac monitoring devices and provide ambulatory monitoring services directly to their patients, while others outsource these services to third-party providers, including IDTFs.

Opportunities in Monitoring for Undiagnosed Arrhythmias

A substantial portion of patients with clinically actionable arrhythmias, including atrial fibrillation, remain undiagnosed due to the intermittent and often asymptomatic nature of these conditions. We estimate that in 2025 approximately 27 million individuals in the United States may be at elevated risk for undiagnosed arrhythmias. Undiagnosed and untreated arrhythmias may result in significantly higher healthcare resource utilization and cost, potentially avoidable serious medical events, and poorer outcomes. Real-world evidence across Medicare and commercially-insured populations indicates that patients with arrhythmias experience higher rates of emergency department visits, inpatient hospitalizations, readmissions, and overall healthcare expenditures compared to similar patients without arrhythmias, particularly among those with comorbid conditions such as type 2 diabetes ("T2D"), chronic obstructive pulmonary disease ("COPD"), chronic kidney disease, and others.

Clinical studies and guideline updates support the use of extended ambulatory monitoring to improve detection of arrhythmias compared to short-duration monitoring modalities. Evidence from randomized trials and real-world claims analyses suggests that earlier identification of arrhythmias using long-term continuous monitoring is associated with fewer acute care events and a shift toward more appropriate outpatient management over time. We believe iRhythm is uniquely positioned to address this opportunity through our scalable service model, long-term continuous monitoring capabilities, extensive clinical evidence base, and proprietary artificial intelligence. Our services are increasingly utilized by innovative, value-based and risk-bearing care organizations seeking to proactively identify arrhythmias within defined patient populations, particularly those with elevated clinical risk.

Furthermore, peer-reviewed real-world evidence demonstrates that proactive ACM generates meaningful healthcare cost savings, particularly in high-risk populations. Studies published in 2024 and 2025 examining patients with T2D and COPD found that patients who developed arrhythmias incurred 1.6–1.8x higher annual costs of care — up to $46,484 versus $30,802 for patients with both T2D and COPD — driven by hospitalization and emergency department visit rates more than two times higher than matched controls. Importantly, T2D patients monitored with ambulatory ECG devices experienced 70% fewer hospitalizations, 44% fewer 30-day readmissions, and nearly 50% fewer emergency department visits compared to unmonitored patients, while monitored COPD patients with arrhythmia saw approximately 30% lower hospitalization incidence and related costs, demonstrating that earlier detection meaningfully bends the cost curve in these patient cohorts.

However, not all monitoring modalities deliver equivalent value. The Cardiac Ambulatory Monitor EvaLuation of Outcomes and Time to Events (“CAMELOT”) study of 287,789 Medicare beneficiaries and the Assessment of Variation in AmbuLatory Cardiac MONitoring (“AVALON”) study of 428,707 commercially insured patients found that LTCM with Zio achieved the highest diagnostic yield, the shortest time to diagnosis, and the lowest total healthcare expenditures, while Holter monitors were 50% less likely, event monitors 42% less likely to detect a specified arrhythmia, and LTCM competing devices 1.4x to 4.3x more likely to require costly retesting. CAMELOT further demonstrated that long-term continuous monitoring was associated with 180 fewer emergency department visits, 80 fewer inpatient hospitalizations, and 920 fewer outpatient visits per 1,000 patients compared to Holter. As the market leader delivering more than 70% of LTCM services in the United States as of 2025, we believe our Zio platform is uniquely positioned to deliver this value as payers increasingly prioritize diagnostic accuracy and first-test resolution to reduce total cost of care.

Over time, we intend to support targeted, evidence-based monitoring strategies that leverage data-driven risk stratification and integrate seamlessly into existing clinical workflows. These efforts are designed to expand access to care, improve clinical outcomes, and inform future growth opportunities, while remaining aligned with our disciplined approach to investment, commercialization, and regulatory compliance.

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Our Products and Services

Our iRhythm ACM Systems deliver a proprietary, patient-friendly design that enables between 98%-99% patient compliance with minimal ECG data noise or artifact, and the iRhythm Services thereby potentially deliver high clinical accuracy to enable physicians diagnosing arrhythmias and reducing the cost of care for healthcare systems by avoiding costly downstream adverse events. We currently offer three iRhythm ACM System options — the Zio monitor System, the Zio XT System, and the Zio AT System.

ACM monitors are designed to provide high-quality, accurate data with patient compliance for up to 14 days of wear time.1-6

MKT1915.01. 1. Data on file. iRhythm Technologies; 2022-2023. 2. Data on file. iRhythm Technologies; 2019. 3. Data on file. iRhythm Technologies; 2022. 4. Zio XT Clinical Reference Manual, iRhythm Technologies. 5. Zio AT Clinical Reference Manual. iRhythm Technologies. 6. Zio monitor Instructions for Use. iRhythm Technologies. *Continuous, uninterrupted refers to the recording of ECG data. Zio AT Gateway transmissions may be impacted by a variety of factors. See Product Labeling for more information. †Zio AT is contraindicated for critical care patients. ‡Do not use Zio AT for patients with symptomatic episodes where variations in cardiac performance could result in immediate danger to the patient or when real-time or in-patient monitoring should be prescribed. Refer to the Zio AT labeling and Clinical Reference Manual for full contraindications.

The Zio Monitoring Solutions

The Zio monitor System is a prescription-only, remote ECG monitoring system that consists of a patch ECG monitor (“Zio monitor”) that records the electric signal from the heart continuously for up to 14 days and the Zio ECG Utilization Software (“ZEUS”), which supports the capture and analysis of ECG data recorded by the Zio monitor at the end of the wear period, including specific arrhythmia events detected by ZEUS. The Zio XT System is the previous generation of the Zio monitor System and is a prescription-only, remote ECG monitoring system that consists of a patch ECG monitor (“Zio XT”) that records the electric signal from the heart continuously for up to 14 days and ZEUS, which supports the capture and analysis of ECG data recorded by the Zio XT at the end of the wear period, including specific arrhythmia events detected by ZEUS.

Zio monitor is 72% smaller, 62% lighter, and 23% thinner than Zio XT, attributes which have contributed to a positive impact on patient experience, including improved patient satisfaction, and associated improvement in device wear times. Furthermore, Zio monitor incorporates a breathable adhesive construct, which enhances the patient experience by removing moisture otherwise captured next to the patient’s skin, as well as Bluetooth communication capabilities and improved processing efficiency.

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Zio monitor Device and Zio XT Device

The Zio AT System is a prescription-only, remote ECG monitoring system that similarly consists of a patch-based ECG monitor (“Zio AT”) that records the electric signal from the heart continuously for up to 14 days and ZEUS, but which also incorporates the Zio AT wireless gateway that provides connectivity between Zio AT and ZEUS during the patient wear period. The wireless gateway, slightly larger than a smart phone, is provided to the patient at the time of Zio AT application on the patient and collects and transmits data from the Zio AT to the cloud via a long-term evolution (“LTE”) cellular protocol.

Zio AT and Wireless Gateway

We support physician and patient use of our iRhythm ACM Systems through our Medicare-enrolled IDTF and qualified technicians, who perform the technical monitoring services associated with a physician’s order for long-term continuous monitoring or MCT monitoring services. Long-term continuous monitoring services (the “Zio LTCM Service”) and MCT services (the “Zio MCT Service”) are diagnostic medical procedures typically ordered by physicians for patients not suspected of having life-threatening arrhythmias, but who are suspected of having infrequent, difficult-to-detect, or asymptomatic arrhythmias. When physicians order long-term continuous monitoring services with our iRhythm ACM System, our biosensor technology collects an uninterrupted, long-term continuous recording of ECG data for up to 14 days and delivers a comprehensive end-of-wear report, which includes specific arrhythmia events detected by the ZEUS algorithm upon return of Zio monitor or Zio XT (and with Zio AT, each, a “Zio patch”) and analysis of the stored data by qualified technicians. A Zio patch typically collects approximately 1.5 million heartbeats of data for each patient during a single wear period of up to 14 consecutive days.

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After we receive a Zio monitor device at our IDTF, the ECG data is uploaded to our secure cloud and preliminary findings are generated by our proprietary FDA-cleared deep learning algorithms. Each report is then validated by qualified technicians and sent to the patient’s prescribing physician who may access the Zio report on our proprietary, web-based portal, referred to as ZioSuite, and also through our Electronic Health Record (“EHR”) connections or ZioSuite mobile apps. Our technicians also notify physicians of certain potentially clinically actionable arrhythmias according to the ordering physician’s specified notification criteria.

ZioSuite Web Portal Via Desktop or Mobile Application

For the Zio MCT Services, Zio AT and its wireless gateway also offer the additional capability of providing actionable transmissions during the wear period to assist physicians in diagnosing and treating patients in situations where their physician has determined that there is a medical need to receive more clinically actionable information during wear. For the Zio MCT Services, physicians will receive daily reports, routine reports, and notifications from qualified technicians if there are clinically actionable events that meet predetermined and physician-specified notification criteria.

While wearing a Zio patch, patients can mark when symptoms occur by pressing a trigger button on the device and separately recording contextual data like activities and circumstances in a written symptom diary or digitally via the myZio application. This allows physicians to match symptoms and activity with ECG-based findings. The Zio patch monitors are not available for sale outside of use with our iRhythm Services. The Zio patch monitors include the following features:

•patented clear, flexible, lightweight, wire-free design;

•unobtrusive and inconspicuous profile;

•proprietary adhesive backing designed to keep the patch-based monitor device securely in place for the duration of the prescribed wear period;

•water-resistant functionality, allowing patients to shower, sleep, and perform normal daily activities, including moderate exercise;

•hydrogel electrodes and a compliant mechanical design to deliver a clear ECG with minimal artifact from movement;

•large symptom button, or patient trigger, that is easy to find and press;

•indicated single application wear period of up to 14 days (for longer prescribed wear periods for MCT services, additional Zio ATs and gateways can be provided); and

•sufficient battery power for the entire wear period, without the need to recharge or replace batteries.

Clinical-grade Wearables

We believe that there is a clinical need and an opportunity to expand our products and services with clinical-grade wearables to detect and characterize arrhythmias while integrating with clinicians’ workflows. As part of this expansion strategy, we have developed proprietary photoplethysmography ("PPG") algorithms designed to be integrated into a wearable device and utilized with our clinically integrated ZEUS System, a solution that is intended to be incorporated into clinical care delivery and assist healthcare providers in identifying and monitoring Afib. We

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are evaluating potential opportunities to leverage our PPG algorithms and ZEUS System with PPG-based wearables, and we intend to further pursue development opportunities on a wearable platform in the future.

The iRhythm Difference

We believe there are strong benefits offered by our 14-day wear time, by the diagnostic yield possibly achieved through our technology, and by the clinical accuracy of our Zio report as enabled by our proprietary deep-learned artificial intelligence that can help to reduce inaccuracies in computerized ECG interpretations and improve the efficiency of expert human ECG interpretation. This is supported by more than 135 original scientific research manuscripts and a robust, growing body of clinical evidence by third-party researchers.

Among this compendium of clinical evidence are multiple studies which demonstrate significant increases in arrhythmia detection through a 14-day monitoring time such as with Zio LTCM Services, as compared to shorter-term 24- to 48-hour monitoring, such as performed as with standard Holter devices. Longer monitoring times with a consistent ECG signal of consistent quality permit detection of infrequent arrhythmias. Other publications illustrate high patient compliance with a 14-day prescribed wear time and low ECG signal artifact, with wear times routinely above 13 days and percent analyzable time above 95%. Additionally, data from the Zio LTCM Service has been used in development of proprietary artificial intelligence, including a deep-learned neural network model which has been shown to meet or exceed the performance of cardiologists in detection of 12 arrhythmia types. In clinical settings, we believe that this approach could reduce the number of misdiagnosed computerized ECG interpretations and improve the efficiency of expert human ECG interpretation by accurately triaging or prioritizing the most urgent conditions.

Long-term, continuous monitoring maximizes diagnostic yield1

MKT1915.01. 1, Turakhia MP, Hoang DD, Zimetbaum P, et al. Diagnostic utility of a novel leadless arrhythmia monitoring device. Am J Cardiol. 2013;112(4):520-524. doi:10.1016/j.amjcard.2013.04.017

Taken together, we believe that these elements are differentiators for iRhythm's Services in the diagnosis and treatment of cardiac arrhythmias and can lead to improved clinical outcomes, enhanced patient experience, high physician and healthcare staff satisfaction, and reduced cost of care to healthcare systems. This was demonstrated by the results from the CAMELOT and AVALON studies which evaluated over 700,000 diagnostic-naive patients across Medicare fee-for-service ("FFS") and commercial populations through two landmark real-world studies. The CAMELOT and AVALON studies offered robust insight into the iRhythm ACM Systems' effectiveness in detecting meaningful arrhythmias in first-time monitoring patients, demonstrating that our LTCM Service had the highest arrhythmia diagnostic yield, lower likelihood of repeat testing, reduced inpatient hospitalizations, fewer emergency department visits, and overall lower healthcare resource utilization compared to all other monitoring services.

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MKT1915.01. 1. Reynolds et al. Comparative effectiveness and healthcare utilization for ambulatory cardiac monitoring strategies in Medicare beneficiaries. Am Heart J. 2024;269:25-34. doi: 10.1016/j.ahj.2023.12.002 2. Russo et al. Assessment of variation in ambulatory cardiac monitoring among commercially insured patients. Am J Manag Care. Published online August 13, 2025. doi:10.37765/ajmc.2026.89782 3. Zio LTCM service refers to Zio XT and Zio monitor service. 4. The Zio service facilitates a diagnosis as determined by a physician. 5. In AVALON, arrhythmias were defined by a panel of clinical experts and study investigators. 6. In CAMELOT, A specified arrhythmia refers to an arrhythmia encounter diagnosis as per Hierarchical Condition Categories (HCC) 96.

Our Strategy

Our mission is to boldly innovate to create trusted solutions that detect, predict, and prevent disease. We execute this mission through a focused strategy that builds on our leadership in ambulatory cardiac monitoring, expands access to care, and selectively extends our platform into adjacent clinical opportunities, while maintaining operational discipline and scalability.

•Leading and Expanding Within the Core Ambulatory Cardiac Monitoring Market. iRhythm is a leading provider of ambulatory cardiac monitoring services in the United States, with approximately 40% penetration of the core ambulatory cardiac monitoring market. Our strategy is anchored in our products' continued leadership in long-term continuous monitoring, which we believe offers high diagnostic yield, clinical accuracy, and efficiency compared to short-duration or event-based monitoring modalities.

We intend to further penetrate the core market by expanding utilization within cardiology and electrophysiology practices while increasing adoption across additional clinical specialties and settings, including primary care. We believe our differentiated combination of patient-friendly, long-term wearable biosensors, proprietary FDA-cleared artificial intelligence algorithms, and integrated digital workflows enables physicians to obtain diagnostic certainty in a single test, improving patient care while reducing downstream healthcare utilization.

Marketing, physician education, and continued publication of peer-reviewed clinical evidence remain central to this strategy. We also continue to expand EHR integrations to streamline ordering, reporting, and clinical decision-making, which we believe supports sustained growth within existing and new accounts.

•Unlocking Market Expansion Through Access, Evidence, and Artificial Intelligence. We believe the ambulatory cardiac monitoring market extends well beyond traditionally symptomatic patients and that significant opportunity exists to expand access earlier in the care pathway. Capacity constraints in cardiology, coupled with a growing prevalence of arrhythmias and an aging population, are driving increased adoption of monitoring solutions in primary care and integrated delivery networks.

Our strategy emphasizes expanding adoption in primary care and other non-cardiology settings by positioning our services as a rule-in and rule-out diagnostic tool that enables efficient triage and referral. We believe this approach improves access to care, reduces unnecessary specialist visits, and supports more timely diagnosis and treatment.

In parallel, we are pursuing proactive monitoring strategies focused on patients at risk for undiagnosed arrhythmias. With an estimated 27 million individuals as of 2025 in the United States potentially at elevated risk for undiagnosed arrhythmias, we believe iRhythm is uniquely positioned to support population health initiatives through scalable, evidence-based monitoring programs.

Our extensive repository of curated ECG data, combined with external data sources and advanced artificial intelligence, underpins our efforts to improve identification, prediction, and stratification of arrhythmia risk. We believe these capabilities differentiate our platform and enable more targeted, efficient monitoring strategies over time.

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•Pursuing international expansion opportunities. While the United States remains our primary market, we are selectively expanding internationally in geographies with established regulatory pathways, reimbursement potential, and unmet clinical need. Our international strategy prioritizes disciplined investment, local clinical evidence generation, and reimbursement progression.

We have established a commercial presence in the United Kingdom, selected European countries, and Japan, which collectively represent an estimated three million existing ambulatory cardiac monitoring services performed annually. We intend to scale these markets deliberately over the medium to long term, focusing on embedding our services into clinical practice and pursuing reimbursement pathways that support long-term sustainability, and we intend to evaluate additional market opportunities in the future.

•Extend the Zio Platform Into Adjacent Clinical Opportunities. We are selectively investing in opportunities that have the potential to extend our core platform into adjacent clinical areas where arrhythmias intersect with other chronic conditions and where our existing capabilities can be leveraged efficiently. These include:

◦Obstructive sleep apnea patients, with an estimated prevalence of approximately 40 million in the United States. Based on a systematic literature review of original clinical studies published between January 2019 and December2024, approximately 50% of patients with Afib may also have sleep apnea and there is a large prevalence of patients with undiagnosed sleep apnea.

◦Heart failure patients, with an estimated prevalence of over 8.5 million in the United States by the year 2030. Atrial fibrillation and heart failure share many antecedent risk factors, and approximately 40% of people with either Afib or heart failure will develop the other condition. Total costs for heart failure in the U.S. are expected to reach $70 billion by 2030.

◦Patients with hypertension, with an estimated prevalence of over 120 million in the United States in 2020. Up to 90% of patients with Afib may also have hypertension.

Our approach to adjacent markets is deliberate and evidence driven. We intend to prioritize opportunities that integrate naturally with existing physician workflows, leverage our data and artificial intelligence capabilities, and align with our long-term focus on scalable, disciplined growth. We have initiated focused pilots and development efforts that are intended to inform future investment decisions.

•Advance Our Product Portfolio and Technology Platform. We continue to invest in advancing our system portfolio and digital platform to address evolving clinical needs. This includes ongoing innovation in our wearable biosensors, data analytics, and reporting capabilities, as well as the development of next-generation mobile cardiac telemetry solutions.

Our next-generation MCT device, for which a 510(k) application was submitted to FDA in the third quarter of 2025, is designed to enhance patient and physician experience through improved form factor, extended wear duration, enhanced detection algorithms, and richer clinical insights. We also continue to evaluate opportunities to incorporate additional sensing modalities and wearable technologies where they complement our core platform.

Sales and Marketing

We directly market our iRhythm Services in the United States to healthcare professional through our internal organization comprised of sales representatives, field billing specialists, and customer experience representatives. Our sales team focuses on initial introduction of our iRhythm Services to those participants that are instrumental to the decision-making process for ambulatory cardiac monitoring, which include physician practices and healthcare systems. We also focus on continuing efforts to ensure healthcare professionals are knowledgeable about the clinical benefits and economic value of the iRhythm Services. We continue to invest in our sales force and focus on ensuring we optimize the structure of our U.S. sales organization to expand the current customer account base and support adoption of the iRhythm Services.

We market our iRhythm Services to a variety of physician specialties including general cardiologists, electrophysiologists, primary care physicians, neurologists, and other physician specialists who diagnose and manage care for patients with arrhythmias. We have found success focusing on integrated delivery networks (“IDNs”), in which large networks of facilities and providers work together to offer a continuum of care to a specific geographic area or market, as well as with risk-bearing entities as our iRhythm ACM Systems become a key tool in population health management. Focusing on sales to these customer programs gives us the opportunity to conduct a holistic sale for health systems interested in making value-based purchasing decisions.

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In January 2021, we established a small direct sales and clinical infrastructure in Bagshot, Surrey in England to service the UK market. We have since focused efforts on the introduction of our iRhythm Services using the Zio XT System into new accounts and market access efforts, in particular through orders made by NHS Trusts and Hospitals. Additionally, in Europe, we have built a small sales force covering Switzerland, Austria, and the Netherlands, have entered into a relationship with a vendor in the Netherlands to distribute our products in European countries other than Spain and to fulfill customer orders and process returns of devices from European customers. In addition, we have entered into a distributor relationship with a vendor in Spain to distribute our products in Spain. In Japan, we utilize the services of a third-party distributor to market and sell our products and services, to fulfill customer orders, and to process returns of devices from Japanese customers.

Competition

The market for remote cardiac monitoring is competitive, characterized by rapid change resulting from technological advances, scientific discoveries, and other market activities of industry participants.

In providing our iRhythm Services, we compete with BioTelemetry, Inc. (acquired by Royal Philips), Preventice Solutions, Inc. (acquired by Boston Scientific, Inc.), and Bardy Diagnostics, Inc. (acquired by Hill-Rom Holdings, Inc. now part of Baxter International, Inc.) ("BardyDx") to offer remote cardiac monitoring technology and also function as diagnostic service providers. We also compete with companies that sell traditional, 24-to-48-hour Holter monitors, including GE Healthcare, Philips Healthcare, and Spacelabs Healthcare Inc., as well as Welch Allyn Holdings, Inc. ("Welch Allyn") and Mortara Instrument, Inc. (both acquired by Hill-Rom Holdings, Inc. now part of Baxter International, Inc.).

Many of our competitors have substantially greater financial, manufacturing, marketing, and technical resources than we do. Furthermore, many of our competitors have well-established brands, widespread distribution channels, broader product offerings, and an established customer base.

These competitors have also developed patch-based cardiac monitors that have received FDA and foreign regulatory clearances. We are also aware of small start-up companies entering the patch-based cardiac monitoring market. Large medical device companies may continue to acquire or form alliances with these smaller companies to diversify their product offering and participate in the digital health space. These competitors and potential competitors may introduce new products and services that directly or indirectly compete with our iRhythm Services and iRhythm ACM Systems.

Future competition may also come from manufacturers of wearable fitness products or large information technology companies focused on general health and wellness. For example, in 2021 and 2022, Apple Inc. and Fitbit each respectively added capabilities on their watch platform to measure non-continuous ECG and to alert users to the potential presence of irregular heartbeats suggestive of asymptomatic Afib.

We believe the principal competitive factors in our market include:

•ease of use, comfort, and unobtrusiveness of the device for the patient;

•quality and clinical validation of the deep-learned algorithms used to detect arrhythmias;

•concise and comprehensive reports supporting efficient physician interpretation;

•ease of use of service workflow for physicians and supporting clinicians;

•digital tools for data management, including the myZio mobile app, website tools, and EHR integration;

•contracted rates with third-party payors;

•government reimbursement rates associated with our iRhythm Services and supporting iRhythm ACM Systems;

•quality of clinical data and publications in peer-reviewed journals;

•size, experience, knowledge, and training of sales and marketing teams;

•availability and reliability of sales representatives and customer support services;

•workflow protocols for solution implementation in existing care pathways;

•reputation of existing device manufacturers and diagnostic service providers; and

•relationships with physicians, hospitals, administrators, and other third-party payors.

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Manufacturing and Quality Assurance

We currently manufacture our iRhythm ACM Systems, including the Zio monitor System and Zio AT System, in our leased facility in Cypress, California. This facility is approximately 69,000 square feet (of which 34,000 square feet is used for manufacturing) and provides space for our manufacturing and production operations, including inspection, assembly, testing, packaging, labeling, storage, and shipping. We believe this manufacturing facility has the capacity to meet our manufacturing needs for at least the next five years.

Outside suppliers are the source for components and sub-assemblies in the production of the iRhythm ACM Systems. Any significant supplier of a critical component, such as the circuit boards for the iRhythm ACM Systems provided by contract electronic manufacturers, is managed through our manufacturing team that is focused on reducing supply chain risk. These suppliers are evaluated, approved, and monitored by our quality team to ensure conformity with the specifications, policies, and procedures applicable to our devices.

Our manufacturing operations are subject to regulatory requirements of FDA (including those in its implementing regulations of the Food, Drug, and Cosmetic Act, the Quality System Regulation, which amendments took effect February 2, 2026, with the updated regulations referred to as the Quality Management System Requirements or "QMSR"), the Medical Devices Regulation 2017/745 of the European Parliament and of the Council (“EU MDR”), the UK Medical Device Regulations 2002 (“UK MDR”), and the Japanese medical device Quality Management System ("QMS"). We are also subject to applicable requirements relating to the environment, waste management, and health and safety matters, including measures relating to the release, use, storage, treatment, transportation, discharge, disposal, sale, labeling, collection, recycling, treatment, and remediation of hazardous substances.

We purchase certain components and materials used in manufacturing from single sources due to quality considerations, costs, or constraints resulting from regulatory or other requirements. As of December 31, 2025, those single sources include suppliers of application-specific integrated circuits used in our transmitters, seals used for the applicators, and certain polymers used to synthesize polymeric membranes for our sensors.

Our manufacturing facilities are also ISO certified (EN ISO 13485:2016). We have registered our device establishments with FDA and with the UK’s Medicines & Healthcare products Regulatory Agency (“MHRA”). Additional EU registrations may be sought in EU member states in the future by our EU authorized representative as appropriate.

Third-Party Reimbursement

We receive revenue for the iRhythm Services primarily from third-party payors, which include commercial payors and government agencies, such as the CMS. Third-party payors require us to identify the service for which we are seeking reimbursement by using a Current Procedural Terminology (“CPT”) code set maintained by the American Medical Association (“AMA”). These CPT codes are subject to periodic change and update, which will impact the reimbursement rates for our iRhythm Services.

For the year ended December 31, 2025, we received approximately 83% of our revenue through third-party payors, which includes approximately 24% of our total revenue from the Medicare program. As we continue to contract with more commercial payors and the patient population ages into eligibility for the Medicare Advantage program, we believe more of our revenue will convert to commercial payor billing.

Our clinical centers are enrolled in the Medicare program as IDTFs, which allows us to bill CMS directly for our iRhythm Services. To maintain enrollment, we must meet the CMS IDTF supplier standards, including having an independent medical director for oversight and qualified technicians who support the analysis of ECG data captured by the Zio patches as part of our iRhythm Services.

For additional information on third-party reimbursement, please see our Risk Factor titled “If reimbursement or other payment for our iRhythm Services is reduced or modified in the United States, including through cost containment measures or changes to policies with respect to coding, coverage, and pricing, our business could suffer.”

Research and Development

We focus our research and development efforts on the ongoing development and expansion of patch-based monitoring devices and related services in alignment with our strategy. We employ engineering and research and development staff to focus on sustaining achieved improvements as well as delivering future innovations. Our research and development activities are focused on:

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•Continuous improvement and extensions to existing products and services. We are continuously working to improve our devices and services to increase patient comfort, improve product quality and operational scalability, and enhance security.

•International expansion. We are working on expanding our infrastructure and ensuring global regulatory compliance as we identify appropriate opportunities for international growth.

•Advancing our technology offering. Our product portfolio includes patch-based solutions (utilized in our existing Zio monitor System, Zio AT System, and Zio XT System) and is planned to include the pending Zio MCT device for which we submitted an application to FDA in 2025. We continue to explore wearable solutions as well as patch-based sensors with additional parameters beyond ECG, but these solutions are in development and will require future FDA clearances and other approvals.

•Customer workflow optimization. We have initiatives that aim to increase customer productivity by optimizing workflow through easier patient enrollment, report access, and interpretation, in addition to integrating the reports from our iRhythm Services directly into EHRs.

•Data analytics. We are focused on improving and enhancing our back-end, deep-learning analytic platform, building on our core competency in data analytics to drive improved speed and accuracy.

•Developing clinical evidence. We frequently provide support to third parties conducting clinical studies that further support the benefits of the iRhythm ACM Systems, including clinical research in areas such as obstructive sleep apnea, hypertension, predictive features, and patient wearables.

•Continuing to solidify our footprint in digital healthcare. Using our repository of ambulatory ECG patient data, as well as our partnerships in the broader chronic disease space, we will continue to look for ways to create value-driving opportunities in digital healthcare, such as expansion of indications for the iRhythm ACM Systems, new therapeutic discoveries, development of an analytical engine for ambulatory consumers, other medical data and payor and provider decision support, and the potential for more complete system integration with large health systems.

We have supported clinical studies conducted by leading physicians and clinicians to explore and develop new techniques and applications for our iRhythm ACM Systems, and other clinical and research activities, including healthcare economic outcomes research.

Our research and development activities consist of software development, algorithm and product development, regulatory affairs, and clinical research. Our research and development expenses (excluding acquired in-process research and development) were $84.6 million, $71.5 million, and $60.2 million for the years ended December 31, 2025, 2024, and 2023, respectively.

Technology License Agreement with BioIntelliSense, Inc.

On August 30, 2024, iRhythm Technologies entered into a Technology License Agreement (as subsequently amended, the “License Agreement”) with BioIntelliSense, Inc. (“BioIS”), pursuant to which (i) iRhythm Technologies will receive a perpetual fully paid up license to certain of BioIS’ intellectual property, technology and products for research, development and commercialization of potential next generation products and services in certain fields of use, including (x) an exclusive license to develop and commercialize pulse oximetry, accelerometry, and trending non-invasive blood pressure technologies for use within our ambulatory cardiac monitoring products and services and (y) a limited, non-exclusive license to develop and commercialize products and services for use in unattended, home-based diagnostic testing and assessment of sleep apnea, and (ii) iRhythm Technologies and BioIS agreed to negotiate in good faith a supply agreement for pulse oximetry hardware.

Under the terms of the License Agreement, iRhythm Technologies paid BioIS an upfront fee of $15.0 million in cash consideration in acceptance of the initial transfer of certain licensed technologies and data following the execution of the License Agreement. In connection with the License Agreement, iRhythm Technologies also purchased an aggregate of $40.0 million of convertible promissory notes from BioIS (the “Convertible Notes”), of which $20.0 million (“Milestone Notes”) were designated for satisfaction of our regulatory milestone payment obligations. The Milestone Notes, plus accrued and unpaid interest, if any, shall be cancelled, if outstanding, upon the achievement of these regulatory milestones up through December 31, 2026. In June 2025, BioIS achieved the first of two regulatory milestones. As of December 31, 2025, we and BioIS are in the process of completing all required contractual conditions to cancel $10.0 million in Milestone Notes plus accrued and unpaid interest.

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Intellectual Property

To establish and protect our proprietary and other intellectual property rights, we rely on a combination of trademark, copyright, patent, trade secret, and other intellectual property laws, and employment, non-disclosure and invention assignment agreements, and other protective contractual provisions with our employees, contractors, consultants, suppliers, partners, outside scientific collaborators, and advisors, and other third parties. In addition, we have entered into licenses in the ordinary course of business relating to a wide array of technologies or other intellectual property rights or assets.

We hold patents and pending patent applications in the United States and other parts of the world which, in aggregate, we believe to be of importance in the operation of our business. As of December 31, 2025, we owned, or retained an exclusive license to, 59 issued patents from the U.S. Patent Office (“USPTO”) (comprised of 55 Utility patents and 4 Design patents), 16 issued patents from the Japanese Patent Office, seven issued patents from the Australian Patent Office, five issued patents from the Canadian Patent Office, seven issued patents from the European Patent Office (validated and providing protections in the countries of Austria, Belgium, Denmark, Finland, France, Germany, Ireland, Italy, Luxembourg, Netherlands, Norway, Spain, Sweden, Switzerland, the UK, and the Unitary Patent Court), seven issued patents from the Korean Patent Office, four issued patents from the Chinese Patent Office, and one issued patent from the Indian Patent Office. Our U.S. issued patents as of December 31, 2025, are set to expire over a range of years, from November 2028 to August 2041, subject to any extensions. As of December 31, 2025, we had 65 pending patent applications globally, including 22 non-provisional applications in the United States, eight applications in the European Patent Office, six applications in Japan, twelve Patent Cooperation Treaty ("PCT") International applications, four applications in Korea, three applications in each of China and India, two applications in Canada, and one application in Australia.

Our patents and patent applications seek to protect aspects of our core technologies and our product concepts for ambulatory cardiac monitoring. We believe that our patent position provides us with sufficient rights to protect our current and proposed commercial products and services. However, our patent applications may not result in issued patents, and any patents that have been issued or might be issued may not protect our intellectual property rights. We are currently party to patent litigation initiated by Welch Allyn and BardyDx as further described under "Legal Proceedings" and we cannot predict the outcome of such litigation. We also rely on trade secrets, technical know-how, and continuing innovation to develop and maintain our competitive position.

As of December 31, 2025, our trademark portfolio contained (i) U.S. trademark registrations for the marks IRHYTHM, KNOW YOUR RHYTHM, ZIO, MYZIO, ZIO SUITE, and ZIO AT and one pending U.S. trademark application for the mark ZIO MCT, (ii) registered trademarks for the mark IRHYTHM in the EU, Australia, Austria, Canada, China, Denmark, Finland, France, Germany, Italy, Japan, Norway, Sweden, Switzerland, and the UK, (iii) trademark registrations for the mark ZIO in the EU, Australia, Canada, China, Japan, Norway, Switzerland, and the UK, (iv) trademark registrations for the mark MYZIO in the EU, Canada, the UK, (v) trademark registrations for the mark ZIO MCT in the EU, Japan, Switzerland, and the UK, and (vi) trademark registrations for the mark ZIOSUITE in the EU and the UK.

Regulation

Based on the nature of the services we provide, the medical devices used to deliver our services, and the ways in which payment is available for our services, we are subject to a complex spectrum of intersecting laws and regulatory frameworks.

Our facilities in Illinois, California, and Texas are enrolled in the Medicare program as IDTFs, defined by CMS as entities independent of a hospital or physician’s office in which diagnostic tests are performed by licensed or certified non-physician personnel under appropriate physician supervision. CMS has set certain performance standards that every IDTF must meet in order to obtain or maintain its billing privileges.

We are also regulated as a medical device manufacturer because of our role in the design, development, and manufacturing of the iRhythm ACM Systems used in our iRhythm Services.

The United States has historically been the primary focus of the delivery of our services, but based on our operations we are subject to a range of laws and regulations outside the United States, and we expect the complexity of the global regulatory landscape to which we are subject to continue to increase.

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U.S. Fraud and Abuse Laws and Other Healthcare Compliance Requirements

Medicare is a federal healthcare program administered by CMS that is available to individuals age 65 or over, and certain other individuals. The Medicare program provides, among other things, healthcare benefits that cover most medically necessary care for such individuals, subject to certain deductibles and co-payments. CMS has established guidelines for the coverage and reimbursement of certain products, supplies, and services, including ambulatory cardiac monitoring services. In general, Medicare will only reimburse ambulatory cardiac monitoring services, such as our iRhythm Services, that are reasonable and necessary for the diagnosis or treatment of patients. CMS also administers the Medicaid program, a cooperative federal/state program that provides medical assistance benefits to qualifying low income and medically needy persons. State participation in Medicaid is optional, and each state is given discretion in developing and administering its own Medicaid program, subject to certain federal requirements. All CMS programs are subject to statutory and regulatory changes, retroactive and prospective rate adjustments, administrative rulings, interpretations of policy, intermediary determinations, and government funding restrictions, all of which may materially increase or decrease the rate of program payments to healthcare facilities and other healthcare providers, including those paid for our iRhythm Services.

Because of the significant federal funding involved, the government actively enforces a number of laws and regulations to eliminate fraud and abuse in federal healthcare programs. Our business is subject to compliance with these laws. The most significant of these laws for our business include the federal Anti-Kickback Statute (the “AKS”) and the federal False Claims Act (the “FCA”).

Anti-Kickback Laws

Under the AKS, it is a criminal offense to knowingly and willfully offer, pay, solicit, or receive any remuneration to induce, or in return for purchasing, ordering, or recommending, or arranging for, the purchase or order of items or services (or referrals of the same) reimbursable by a federal healthcare program. The AKS imposes criminal liability for both the party that provides or offers such remuneration and the party that receives or solicits such remuneration. Courts and enforcement agencies interpret the AKS broadly, such that it may be implicated whenever anything of value is provided to a party in a position to generate federal healthcare program business where any one purpose of an arrangement involving remuneration is to induce referrals. Penalties for violations include criminal penalties and civil sanctions such as fines, imprisonment, and possible exclusion from Medicare, Medicaid, and other federal healthcare programs. Many states have adopted laws similar to the AKS. Some of these state prohibitions apply to referral of recipients for healthcare products or services reimbursed by any source, not only CMS programs. The Physician Payments Sunshine Act requires transparency around certain transfers of value and ownership interests that may raise parallel scrutiny of the appropriateness of financial relationships. Notably, some kickback allegations are also interpreted as violations of the FCA.

False Claims Act

The FCA prohibits: (i) knowingly presenting, or causing to be presented, a false or fraudulent claim for payment or approval and (ii) knowingly making, using, or causing to be made or used a false record or statement material to a false or fraudulent claim. Importantly, the FCA provides for “whistleblower” or qui tam actions, which allow a private individual to bring actions on behalf of the federal government alleging that the defendant has violated the FCA and to share in any monetary recovery. The federal government has used the FCA to assert liability on the basis of inadequate care, kickbacks, and other improper referrals, and improper use of CMS billing numbers, as well as allegations of off-label promotion of products, and activities relating to the reporting of discount and rebate information. The FCA is the federal government’s preferred enforcement vehicle for addressing a variety of alleged misconduct and provides for treble damages and civil money penalties ranging from $14,308 to $28,619 per claim as of July 3, 2025. Individuals and entities can also face exclusion from participation in federal healthcare programs and potential criminal penalties, including imprisonment and criminal fines. Additionally, as part of any settlement, the government will occasionally require the entity to enter into a corporate integrity agreement, which imposes certain ongoing compliance, certification, and reporting obligations. In addition, various states have enacted false claims laws analogous to the FCA, and many of these state laws apply where a claim is submitted to any third-party payor and not only a federal healthcare program.

Healthcare Reform

Changes in healthcare policy could increase our costs and subject us to additional regulatory requirements that may interrupt commercialization of our current and future solutions. The Affordable Care Act (“ACA”) substantially changed the way healthcare is financed by both governmental and private insurers, and significantly impacts our industry. Any changes to, or repeal of, the ACA may have a material adverse effect on our results of operations.

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Additionally, for out-of-network or cash pay patients, we may be subject to state and federal surprise billing laws that impose limits on amounts that can be charged to such patients and/or the amount we can receive for out-of-network services from commercial payors. One such law, the federal No Surprises Act, requires covered providers to provide “good faith estimates” to patients and establishes a detailed and potentially costly independent dispute resolution process governing fee disputes with those patients. These laws and regulations may change, and additional implementation regulations are expected for the No Surprises Act, and we anticipate these requirements may apply to our business in the future.

We are subject to risks related to U.S. and international fraud and abuse laws and other healthcare compliance requirements described above, as well as others that are or may be adopted in future. For further details on these risks, see “Risk Factors,” below.

U.S. Food and Drug Administration

Because we develop and manufacture the medical device technology used in the iRhythm Services (the hardware and software elements that FDA regulates as “devices”), we are subject to extensive and ongoing regulation by FDA under the Federal Food, Drug, and Cosmetic Act (“FD&C Act”) and its implementing regulations, as well as other federal and state regulatory bodies in the United States. The laws and regulations govern, among other things, product design and development, preclinical and clinical testing, manufacturing, packaging, labeling, storage, recordkeeping and reporting, clearance or approval, marketing, distribution, promotion, import and export, and post-marketing surveillance and associated regulatory reporting.

Most Class II devices, including Zio monitor, Zio AT, Zio XT, ZEUS and the Zio MCT device for which we are seeking marketing authorization, require 510(k) clearance from FDA in order to be marketed in the United States. A 510(k) submission must demonstrate that the device is substantially equivalent to a device legally in commercial distribution in the United States. After clearance, changes made to devices must be evaluated on an ongoing basis and may trigger the need for additional 510(k) clearances or – depending on the nature of the change – might require a higher level of FDA review (through the de novo premarket approval or (“PMA”) process). To date, our product changes have been managed within the 510(k) framework.

After a device is placed on the market, numerous regulatory requirements continue to apply. These include:

•FDA’s QMSR, which requires manufacturers, including their suppliers, to follow stringent design, testing, control, documentation, and other quality assurance procedures during all aspects of the product lifecycle, including the manufacturing process;

•labeling regulations and FDA prohibitions against the promotion of products for uncleared, unapproved, or off-label uses, including parameters around manufacturer communications with payors and healthcare professionals;

•medical device reporting regulations, which require that manufacturers report to FDA if their device may have caused or contributed to a death or serious injury or malfunctioned in a way that would likely cause or contribute to a death or serious injury if the malfunction were to recur;

•medical device recalls, which require that manufacturers report to FDA any recall of a medical device, provided the recall was initiated to either reduce a risk to health posed by the device, or to remedy a violation of the FD&C Act caused by the device that may present a risk to health; and

•post-market surveillance regulations, which apply when necessary to protect the public health or to provide additional safety and effectiveness data for the device.

After a device receives 510(k) clearance or PMA, any modification that could significantly affect its safety or effectiveness, or that would constitute a major change in its intended use, performance, or functionality may require a new clearance or approval. FDA requires each manufacturer to make this determination initially, but FDA can review any such decision and can disagree with a manufacturer’s determination. If FDA disagrees with the determination not to seek a new 510(k) clearance or PMA approval, FDA may retroactively require a new 510(k) clearance or PMA approval. FDA could also require a manufacturer to cease marketing and distribution and/or recall the modified device until 510(k) clearance or PMA approval is obtained. Also, in these circumstances, the manufacturer may be subject to significant regulatory fines, penalties, and other enforcement actions, such as warning letters.

We have registered appropriate facilities with FDA as a medical device specification developer, manufacturer, or designated complaint handling unit. We have also obtained a manufacturing license from the California Department of Public Health (“CDPH”). FDA and the CDPH have broad post-market and regulatory enforcement powers. We are subject to unannounced inspections by FDA and the Food and Drug Branch of CDPH to determine our compliance with FDA's QMSR and other regulations, and these inspections may include the manufacturing facilities of our suppliers.

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Failure to comply with applicable regulatory requirements can result in enforcement action by FDA, which may include any of the following sanctions:

•warning letters, fines, injunctions, consent decrees, and civil penalties;

•repair, replacement, refunds, recall, or seizure of our products;

•operating restrictions, partial suspension, or total shutdown of production;

•refusing our requests for 510(k) clearance or PMA approval of new products, new intended uses, or modifications to existing products;

•withdrawing 510(k) clearance or PMA approvals that have already been granted; and

•criminal prosecution.

For further details on these risks, see “Risk Factors” below. The manner in which these risks present may also be impacted by the changing enforcement landscape, including in relation to reorganization under current administration policies. For example, DOJ has used both criminal and civil mechanisms to enforce the FD&C Act through the Consumer Protection Branch (“CPB”) of DOJ. Following dissolution of the CPB, on September 25, 2025, DOJ announced a restructuring under which the Civil Division’s litigation work would be consolidated into a new Enforcement & Affirmative Litigation Branch, and the Health and Safety Unit housed within the Fraud Section of DOJ’s Criminal Division is now charged with criminal enforcement of the FD&C Act.

Privacy and Security Regulation

Our business is subject to foreign, federal, and state privacy and security laws concerning the collection, use, analysis, retention, storage, protection, transfer, disclosure, and/or disposal of individually identifiable information including, without limitation, the General Data Protection Regulation (“GDPR”), the Health Insurance Portability and Accountability Act of 1996, as amended by the final regulations promulgated pursuant to the Health Information Technology for Economic and Clinical Health Act (“HITECH”), found in the American Recovery and Reinvestment Act of 2009 (collectively, “HIPAA”), the Telephone Consumer Protection Act, the CAN-SPAM Act, and state privacy, consumer protection, and breach notification laws.

We are subject to risks related to privacy and security regulation. For further details on these risks, see “Risk Factors,” below.

European Union and United Kingdom

In the European Union, the system of regulating medical devices operates by way of a certification for each medical device. Each certified device is marked with the CE mark which shows that the device has a certificate of conformance under the EU MDR. Since May 2021, the EU MDR has been the relevant regulatory framework for devices in the EU, replacing the prior Medical Device Directive. The Zio monitor System and ZEUS are currently marked in the EU under our CE mark under the EU MDR issued by the British Standards Institution ("BSI") in December 2023.

National competent authorities in each member state of the EU oversee the implementation of the EU MDR within their jurisdiction, typically through so-called notified bodies which are certification organizations designated by a member state to conduct third-party conformity assessments (the “Notified Bodies”). The means for achieving the requirements for the CE mark vary according to the nature of the device. Devices are classified in accordance with their perceived risks, similarly to the U.S. system. The class of a product determines the conformity assessment required before the CE mark can be placed on a product. Conformity assessments for our products are carried out as required by Notified Bodies. If a Notified Body of one member state has issued a CE mark, the device can be distributed throughout the EU without further conformance tests being required in other member states, although certain member states may require in-country device registrations after the issuance of the CE mark. The CE mark is contingent upon continued compliance with the applicable regulations and the quality system requirements of the ISO 13485 standard.

Due to UK’s departure from the EU, the MHRA has issued requirements associated with the UK Conformity Assessed (“UKCA”) mark. The UKCA marking is a new UK product marking that is used for goods being placed on the market in Great Britain. It covers most goods which previously required the CE marking, including medical devices. The UKCA requirement became effective on January 1, 2021, and we have obtained a UKCA mark with the BSI, which also serves as our UK Approved Body, for Zio XT and ZEUS. We are also registered with the UK’s Care Quality Commission to carry out diagnostic and screening procedures.

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Additionally, the EU Notified Body and UK Approved Body regularly audit our manufacturing, design, and operational facilities to ensure ongoing ISO 13485 and EU MDR compliance and periodically audit technical design files in accordance with the EU MDR in order to maintain our CE mark or issue a CE mark or UKCA mark for new or updated devices.

Japan

Regulatory authorities in Japan include the Ministry of Health, Labor and Welfare ("MHLW"), which defines policy, issues medical device approvals and enforces regulations; and the PMDA which reviews device applications, conducts scientific assessments and monitors post-market device safety. The Act on Securing Quality, Efficacy and Safety of Products Including Pharmaceuticals and Medical Devices (the "PMD Act") is the principal legislation in Japan governing Medical Devices that provides a comprehensive regulatory framework such as marketing authorization, business licenses, labeling and advertising regulations. Devices are classified in accordance with their perceived risks, similarly to the U.S. and EU systems. Zio monitor and ZEUS (known in Japan as Zio ECG Recording and Analysis System) were approved by MHLW in September 2024 and Zio monitor is currently marketed in Japan.

In addition to product approval, we and other foreign manufacturers must appoint a Japan-based Designated Marketing Authorization Holder ("DMAH") to be the Regulatory and Quality Management System ("QMS") representative to MHLW for pre- and post-market activities. MHLW Ordinance No. 169 governs QMS requirements, largely aligned with ISO 13485:2016 with other Japan-specific provisions and has been incorporated into iRhythm's internal quality management system.

Anti-Bribery and Anti-Corruption Laws

The U.S. Foreign Corrupt Practices Act (“FCPA”) and similar laws in foreign jurisdictions generally prohibit any U.S. corporations and their representatives from offering, promising, authorizing, or making payments, gifts, or transfers of value, directly or indirectly, to any foreign official, political party, or candidate for the purpose of influencing any act or decision of the foreign entity in order to obtain or retain business. The scope of the FCPA includes interactions with certain healthcare professionals and hospital administrators in many countries.

In addition, in Europe, various countries have adopted anti-bribery laws providing for severe consequences in the form of criminal penalties and significant fines for individuals or companies committing a bribery offense. Violations of these anti-bribery laws, or allegations of such violations, could have a negative impact on our business, results of operations, and reputation. For instance, in the UK, under the U.K. Bribery Act 2010, a bribery occurs when a person offers, gives, or promises to give a financial or other advantage to induce or reward another individual to improperly perform certain functions or activities, including any function of a public nature. Bribery of foreign public officials also falls within the scope of the U.K. Bribery Act 2010. An individual found in violation of the U.K. Bribery Act 2010 faces imprisonment of up to 10 years. In addition, the individual can be subject to an unlimited fine, as can commercial organizations for failure to prevent bribery.

Sustainability

To best serve our various stakeholders – including patients, caregivers, employees, investors, and communities – we believe in operating in a sustainable manner according to five core values. These principles guide how we accomplish our mission to drive the success of our business and enable long-term value creation.

•Lead with integrity. We believe that building trust, holding ourselves to the highest standards of ethics, acting with transparency, and being accountable forms the foundation of who we are as a company.

•Solve for the patient. Improving the lives of patients is our passion, so with everything we do, we put patients first, aim to deliver high-quality results, and consider customer needs.

•Think big, go fast. Achieving our vision requires bold action without compromising quality. This is why we strive to be open to new ideas, take intelligent risks, act with a sense of urgency, and learn from failure.

•Collaborate to win. Prioritizing collective success delivers astounding results, so we aim to think holistically and strategically, develop relationships proactively, and work as one team.

•Strive for better. We believe that immense possibility exists at iRhythm, so we are open to embracing change and pursuing opportunities for growth, and we seek diverse perspectives in that pursuit.

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In accordance with these values, we believe that effectively managing sustainability risks and opportunities drives business success and that, when fully integrated into the business, sustainability can provide a competitive advantage. In 2024, we refreshed our sustainability priority assessment to ensure we are aligning with the issues that matter most to our business and stakeholders and, in 2025, we released a refreshed corporate sustainability report to highlight our progress against these priorities.

We made significant progress in many aspects of our sustainability strategy, including:

•Enhancing our quality systems, improved customer experience through EHR integration and innovative product launches, and securing strategic technology licensing agreements to advance connected patient care;

•Refreshing our core values to define the culture we would like to shape going forward;

•Receiving regulatory approval from the PMDA for the Zio fourteen-day, long-term continuous ECG monitoring system in Japan, the world’s second largest market for ambulatory cardiac monitoring (ACM) in 2025;

•Completing our Scope 3 greenhouse gas emissions inventory and achieving 89.5% landfill waste diversion;

•Improving access by launching in Austria, the Netherlands, Spain and Switzerland; and,

•Revising our code of conduct to provide employees with the resources and guidance needed to operate with unquestionable integrity.

Human Capital

As of December 31, 2025, we had approximately 2,400 employees globally. We believe in creating a flexible, productive, and globally connected dispersed workforce. Our work model is comprised of employees spanning remote, hybrid, and fully onsite work arrangements. Work arrangements are determined based on the needs of the role, nature of work, and regulatory requirements. Our approach is designed to empower our global workforce, fostering flexibility and productivity while maintaining a strong company culture.

Inclusion and Belonging

We are committed to being an equal opportunity employer and we prohibit all forms of unlawful discrimination in accordance with applicable law. We believe in the richness and quality of a working environment that is informed by people from all walks of life and strive to create a genuinely inclusive environment. To build on our commitment to inclusion and belonging, we have various initiatives led by our Chief Risk Officer to foster a work environment where everyone feels valued, respected, and empowered to contribute.

Board and Management Oversight

The compensation and human capital management committee of our board of directors has oversight of our culture and human capital management, including our approach to talent recruiting, development, progression and retention, culture, human health and safety, and total rewards. We are committed to nurturing our workforce and have also established a Global Leadership Forum that is led by our Executive Leadership Team to ensure broader alignment across our organization's leadership on key corporate initiatives, company culture, and transformation objectives.

Health and Safety

We believe that to date we have materially complied with applicable health, safety, and environmental laws as well as related company policies and procedures and provide necessary training as appropriate by role and location. In 2023, we published internally our Environmental, Health, and Safety Policy Statement demonstrating our ongoing commitment to the highest standards of environmental, health, and safety performance. We consistently track and evaluate recordable incident rates associated with our various facilities locations. We believe that by integrating sound environmental, health, and safety management practices into all elements of our business and operations, we will consistently deliver innovative and trusted solutions for the patients that we serve, as well as sustain higher standards of employee safety.

Total Rewards

We believe that we employ a fair and merit-based total compensation system, and we evaluate our compensation programs regularly to help ensure that our employees are compensated fairly for their work while fostering a pay-for-performance culture that is aligned with the interests of our stockholders.

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We believe that we offer our employees competitive benefits that follow industry standards and support physical, mental, and financial wellness. We offer health benefits, a 401(k) plan with company match, paid time off and family leave, an Employee Stock Purchase Plan for employees in the United States and the United Kingdom, which allows them to purchase our stock at a discount, and an employee wellness program that is generally available to employees and their families globally with a variety of support services.

Workforce Development

The growth and success of our employees is one of our top priorities as it impacts our overall company performance. We are investing heavily to build in-house tools and resources to support managers and employees. Our core competencies are the foundation for programs and tools being developed to identify top talent, prepare future managers and leaders, and provide equal access to growth opportunities.

We offer a variety of training opportunities, whether focused on building vocational, management, or leadership skills. We facilitate sessions around our core competencies, interview skills, and coaching practices, and we offer a toolbox on our intranet with resources for employees and managers across the employee lifecycle.