Results of Operations and Financial Condition. On November 4, 2026, Onterris, Inc. (the “Company”) issued a press release announcing its financial results for the fiscal quarter ended September 30, 2026. A copy of the press release is furnished as Exhibit 99.1 to this report. The information included or incorporated by reference in this Item 2.02, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission (the “SEC”) and shall not be deemed to be “filed” for purposes…

Director — Janet Risi Field: A director resigned for personal reasons without any stated disagreement with the company, representing a standard board departure.

Material Modifications to Rights of Security Holders. The information set forth under Items 1.01 and 5.03 of this Current Report on Form 8-K is incorporated into this

Entry into a Material Definitive Agreement. On August 5, 2026, the Board of Directors (the “Board”) of Onterris, Inc. (the “Company”) declared a dividend of one preferred share purchase right (a “Right”), payable on August 17, 2026, for each share of common stock, par value $0.000004 per share, of the Company (the “Common Shares”) outstanding on August 17, 2026 to the stockholders of record on that date. In connection with the distribution of the Rights, the Company entered into a Rights Agre…

Entry into a Material Definitive Agreement. On August 5, 2026, the Board of Directors (the “Board”) of Onterris, Inc. (the “Company”) declared a dividend of one preferred share purchase right (a “Right”), payable on August 17, 2026, for each share of common stock, par value $0.000004 per share, of the Company (the “Common Shares”) outstanding on August 17, 2026 to the stockholders of record on that date. In connection with the distribution of the Rights, the Company entered into a Rights Agre…

Results of Operations and Financial Condition. On August 5, 2026, Onterris, Inc. (the “Company”) issued a press release announcing its financial results for the fiscal quarter ended June 30, 2026. A copy of the press release is furnished as Exhibit 99.1 to this report. The information included or incorporated by reference in this Item 2.02, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission (the “SEC”) and shall not be deemed to be “filed” for purposes of Sec…

Material Modifications to Rights of Security Holders. The information set forth under Items 1.01 and 5.03 of this Current Report on Form 8-K is incorporated into this

Results of Operations and Financial Condition. On May 6, 2026, Onterris, Inc. (the “Company”) issued a press release announcing its financial results for the fiscal quarter ended March 31, 2026. A copy of the press release is furnished as Exhibit 99.1 to this report. The information included or incorporated by reference in this Item 2.02, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission (the “SEC”) and shall not be deemed to be “filed” for purposes of Secti…

Results of Operations and Financial Condition. On February 25, 2026, Montrose Environmental Group, Inc. (the “Company”) issued a press release announcing its financial results for the fiscal year ended December 31, 2025. A copy of the press release is furnished as Exhibit 99.1 to this report. The information included or incorporated by reference in this Item 2.02, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission (the “SEC”) and shall not be deemed to be “fi…

COO — James Laws: The filing announces the external appointment of a new Chief Operating Officer, which is a significant management addition but not a departure of an existing executive.

Results of Operations and Financial Condition. On November 4, 2025, Montrose Environmental Group, Inc. (the “Company”) issued a press release announcing its financial results for the fiscal quarter ended September 30, 2025. A copy of the press release is furnished as Exhibit 99.1 to this report. The information included or incorporated by reference in this Item 2.02, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission (the “SEC”) and shall not be deemed to be…

Results of Operations and Financial Condition. On August 6, 2025, Montrose Environmental Group, Inc. (the “Company”) issued a press release announcing its financial results for the fiscal quarter ended June 30, 2025. A copy of the press release is furnished as Exhibit 99.1 to this report. The information included or incorporated by reference in this Item 2.02, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission (the “SEC”) and shall not be deemed to be “filed”…

Other Events. On July 1, 2025, Montrose Environmental Group, Inc. (the “Company”) voluntarily redeemed in full all issued and outstanding shares of the Company’s Series A-2 Preferred Stock (the “A-2 Preferred”), which were held by OCM Montrose II Holdings, L.P (the “Holder”). The Stated Value, as defined in the certificate of designation governing the A-2 Preferred (the “Certificate of Designations”), of the remaining outstanding shares of A-2 Preferred at the time of redemption was $62.2 mil…

Other Events. On May 7, 2025, the Company announced that its Board of Directors has approved a stock repurchase program of up to $40.0 million. The repurchase program does not have a set expiration date.

Results of Operations and Financial Condition. On May 7, 2025, Montrose Environmental Group, Inc. (the “Company”) issued a press release announcing its financial results for the fiscal quarter ended March 31, 2025. A copy of the press release is furnished as Exhibit 99.1 to this report. The information included or incorporated by reference in this Item 2.02, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission (the “SEC”) and shall not be deemed to be “filed” f…

Results of Operations and Financial Condition. On February 26, 2025, Montrose Environmental Group, Inc. (the “Company”) issued a press release announcing its financial results for the fiscal year ended December 31, 2024. A copy of the press release is furnished as Exhibit 99.1 to this report. The information included or incorporated by reference in this Item 2.02, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission (the “SEC”) and shall not be deemed to be “fi…

Director — Vincent Colman: The filing discloses the appointment of a new independent director to fill a newly created board seat, which is a routine governance action rather than an executive departure.

Triggering Events That Accelerate or Increase a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement. On January 13, 2025, Montrose Environmental Group, Inc. (the “Company”) received a notice of conversion from OCM Montrose II Holdings, L.P., the holder of all issued and outstanding shares of the Company’s Series A-2 Preferred Stock (the “A-2 Preferred”), in respect of $60.0 million in Stated Value, as defined in the certificate of designation governing the A-2…

The filing describes the voluntary cancellation of stock appreciation rights, which is a compensatory arrangement rather than a change in management personnel.

COO — Joshua LeMaire: The COO is stepping down from the executive role to become a non-executive advisor, representing a genuine departure from the C-suite but with an orderly transition and continued association with the company.

Results of Operations and Financial Condition. On November 6, 2024, Montrose Environmental Group, Inc. (the “Company”) issued a press release announcing its financial results for the fiscal quarter ended September 30, 2024. A copy of the press release is furnished as Exhibit 99.1 to this report. The information included or incorporated by reference in this Item 2.02, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission (the “SEC”) and shall not be deemed to be…

Results of Operations and Financial Condition. On August 6, 2024, Montrose Environmental Group, Inc. (the “Company”) issued a press release announcing its financial results for the fiscal quarter ended June 30, 2024. A copy of the press release is furnished as Exhibit 99.1 to this report. The information included or incorporated by reference in this Item 2.02, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission (the “SEC”) and shall not be deemed to be “filed”…

Results of Operations and Financial Condition. On May 7, 2024, Montrose Environmental Group, Inc. (the “Company”) issued a press release announcing its financial results for the fiscal quarter ended March 31, 2024. A copy of the press release is furnished as Exhibit 99.1 to this report. The information included or incorporated by reference in this Item 2.02, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission (the “SEC”) and shall not be deemed to be “filed” f…

Other Events On April 17, 2024, Montrose Environmental Group, Inc. (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with J.P. Morgan Securities LLC, William Blair & Company, L.L.C., and Evercore Group L.L.C., as representatives of the several underwriters named therein (collectively, the “Representatives”) relating to the offer and sale by the Company (the “Offering”) of 3,000,000 shares (the “Initial Shares”) of the Company’s common stock, par value $0.00…

Results of Operations and Financial Condition. On February 29, 2024, Montrose Environmental Group, Inc. (the “Company”) issued a press release announcing its financial results for the fiscal year ended December 31, 2023. A copy of the press release is furnished as Exhibit 99.1 to this report. The information included or incorporated by reference in this Item 2.02, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission (the “SEC”) and shall not be deemed to be “fi…