iRhythm (IRTC) Q4 2025 earnings review
Milestone Quarter: First GAAP Profit as Margins Explode
iRhythm delivered a transformational quarter, proving its business model can scale profitably. Revenue grew 27.1% to $208.9M, but the real story is the bottom line: the company posted its first-ever GAAP Net Income ($5.6M) and first full year of positive Free Cash Flow ($34.5M). Operational leverage kicked in hard—Gross Margins expanded to 70.9% and Adjusted EBITDA margin surged to 16.4% (up 470 bps YoY). While FY26 guidance suggests a growth deceleration and margin moderation compared to the Q4 exit rate, the fundamental inflection point has been reached.
🐂 Bull Case
For the first time, iRhythm posted positive GAAP Net Income ($5.6M) and full-year positive Free Cash Flow ($34.5M). This removes the 'cash burn' overhang and proves the unit economics work at scale.
Revenue growth has remained above 20% for five consecutive quarters. Volume is being driven by all cylinders: US core accounts, international expansion, and new innovative health channels.
🐻 Bear Case
FY26 revenue guidance implies ~17% growth, a steep drop from the ~27% pace seen in 25Q4. Management is either sandbagging heavily or seeing saturation signals.
The Q4 Adjusted EBITDA margin was 16.4%, yet management guided FY26 to a range of 11.5-12.5%. This implies a significant step back in profitability, likely due to heavy reinvestment or conservative forecasting.
⚖️ Verdict: 🟢🟢
Bullish. Crossing the threshold to GAAP profitability and positive Free Cash Flow is a massive de-risking event. While the FY26 guidance looks conservative (decelerating growth and margins vs Q4), the underlying execution in Q4 was flawless.
Key Themes
Operational Leverage Kick-In
The gap between revenue growth (+27%) and operating expense growth is widening in favor of profits. Gross margins hit 70.9% (+90 bps YoY) due to manufacturing efficiencies and scale. This leverage drove Adjusted EBITDA from $19.3M last year to $34.3M this quarter.
Guidance vs. Momentum Disconnect
iRhythm exited 2025 with 27% growth and 16.4% EBITDA margins. However, 2026 guidance calls for ~17% growth and ~12% margins. Investors must determine if this is prudent conservatism (sandbagging) or if the company plans a massive spike in OpEx (R&D/Sales) that will eat the recent margin gains.
Innovative Channels & Primary Care
Management highlighted 'innovative health channels' and 'primary care' as key drivers. Moving upstream to detect arrhythmias in asymptomatic or high-risk populations (rather than just symptomatic cardiology patients) expands the Total Addressable Market (TAM) significantly.
Regulatory & Remediation Costs
While net income is positive, the company continues to exclude 'Business transformation costs' and legal expenses from Adjusted EBITDA. The guidance notes explicitly state they cannot reconcile 2026 OpEx due to uncertain items, implying FDA remediation or legal costs remain a fluid variable.
Other KPIs
A major milestone. FY24 saw a cash burn of $30.5M; FY25 flipped to positive generation of $34.5M. Cash balance is healthy at $583.8M, removing any near-term need for dilution.
Accelerating. Up 90 basis points YoY and consistent with the annual trend (70.6% for FY25). Driven by manufacturing efficiencies and volume scale, despite mix shifts to Zio AT.
Accelerating. Up $15M vs the prior year period. The 16.4% margin is a record high, proving the core business is highly profitable before heavy R&D reinvestment.
Guidance
Decelerating. The midpoint implies ~17% YoY growth, significantly lower than the 26.2% growth achieved in FY25. This suggests caution regarding the durability of the recent growth spike or anticipation of tougher comps.
Stable / Decelerating vs Q4 exit. While this represents an improvement over the full year FY25 (9.2%), it is a step down from the 16.4% achieved in Q4 2025. This suggests management plans to ramp up spending or expects Q4 seasonality was an outlier.
Key Questions
Margin Reset in 2026
You achieved a 16.4% Adjusted EBITDA margin in Q4, yet you are guiding to ~12% for FY26. What specific investments or headwinds are causing this 400bps step-down from the exit rate?
Revenue Growth Durability
Guidance implies revenue growth slowing from 27% to 17%. Is this conservatism, or are you seeing saturation in the core US channel?
International Contribution
With the Japan launch and European expansion, why isn't the FY26 growth rate sustaining higher levels? Are international regulatory or reimbursement hurdles slower than anticipated?