Slide 1: 2Q26 Earnings Presentation Addendum
2Q26 Earnings Presentation Addendum August 6, 2026
Slide 2: Disclosures
Disclosures Statements contained herein and in the accompanying oral presentation contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended and Section 21E of the Securities Exchange Act of 1934, as amended. Forward-looking statements may be ident
Slide 3: Disclosures
Disclosures Forward-looking statements speak only as of the date on which they are made and we undertake no obligation to update any forward-looking statement to reflect future events, developments or otherwise, except as may be required by applicable law. Investors are referred to the Onterris fili
Slide 4: Summary
Summary • ONT economic engine remains strong - cash flow expectation for 2026 is largely unchanged despite reduction in revenue • 2026 margins1 expectations are higher with updated guidance (~15.5% at the midpoint versus ~15% at the midpoint of original guidance and 14.0% FY25) • Change in Consolida
Slide 5: Strong Net Service Revenue with Margin Growth
Strong Net Service Revenue with Margin Growth $ in millions 2023 2024 2025 2026 Revised Net Service Revenue (NSR1) Guidance Midpoint Revenue 2023 2023 – 2025 – 2026 Revenue 15% 7% CAGR $830.5 NSR $765.0 16% 11% $696.4 CAGR $624.2 $610.7 $628.0 $529.8 $453.6 Margin1: 17.3% 12.6% 18.1% 13.8% 19.0% 14.
Slide 6: Appendix
) Appendix For Planet & Progress,
Slide 7: Non-GAAP Financial Information
Non-GAAP Financial Information Brand and Resegmentation: On April 17, 2026, Montrose Environmental Group, Inc. rebranded to Onterris, Inc. Beginning in the first quarter of 2026, the Company realigned its reportable segments to reflect updates made to the organizational structure and operating model
Slide 8: Non-GAAP Financial Information (Continued)
Non-GAAP Financial Information (Continued) Management compensates for these limitations by using these measures as supplemental financial metrics and in conjunction with our results prepared in accordance with GAAP. We encourage investors and others to review our financial information in its entiret
Slide 9: Reconciliation of Net Income (Loss) to Adjusted Net Income
Onterris, Inc. 1) Represents non-cash stock-based compensation expenses related to Reconciliation of Net Income (Loss) to Adjusted Net Income option awards issued to employees and restricted stock grants issued to directors and selected employees. 2) Includes financial and tax diligence, consulting,
Slide 10: Reconciliation of Net Income (Loss) to Consolidated Adjusted EBITDA
Onterris, Inc. Reconciliation of Net Income (Loss) to Consolidated Adjusted EBITDA Three Months Ended June 30, Six Months Ended June 30, 2026 2025 2026 2025 Net income (loss) $ 1,366 $ 18,356 $ (11,324) $ (1,003) Interest expense 5,471 4,768 10,937 9,833 Income tax expense 346 988 2,649 3,859 Deprec
Slide 11: Reconciliation of Revenue to Net Service Revenue
Onterris, Inc. Reconciliation of Revenue to Net Service Revenue For the Three Months Ended June 30, For the Six Months Ended June 30, 2026 2025 2026 2025 Revenue $ 186,661 $ 234,543 $ 355,179 $ 412,377 Subconsultants and non-labor direct costs (36,178) (63,007) (66,831) (101,605) Net Service Revenue
Slide 12: Investing for Planet & Progress
Investing for Planet & Progress Our innovative solutions and integrated expertise deliver stronger environmental compliance and performance, generating new value for stakeholders and securing a better future for clients, communities and the ecosystems we all depend on. Thank you for supporting our m
Slide 13: Thank You
Thank You © Onterris • 2Q26 Earnings • 13