Altamira Technologies Corporation

On January 14, 2026, the Company acquired a 100% ownership interest in Altamira Technologies Corporation ("ATC"), a privately owned company, for approximately $340 million in cash and up to an additional $45 million in the event an earn out EBITDA target is exceeded. The Company borrowed $330.0 million under the Credit Agreement to fund the acquisition. Headquartered in McLean, Virginia, ATC enhances Parsons’ defense and intelligence portfolio by delivering advanced analytics, signals intelligence (SIGINT), cyber, missile warning, and space capabilities, complementing the Company’s strengths in all‑domain technology integration and Indo‑Pacific operations, and expanding with intelligence community (IC) customers. In connection with this acquisition, the Company recognized $5.0 million of acquisition-related expenses in “Selling, general and administrative expense” in the consolidated statements of income for the three months ended March 31, 2026, including legal fees, consulting fees, and other miscellaneous direct expenses associated with the acquisition.

The Company agreed to pay the selling shareholders up to an additional $45 million in the event an earn out EBITDA target is exceeded during the fiscal year ended December 31, 2026. In the event that the 2026 EBITDA is less than target, the earn out payment shall be zero. The fair value of the earn out (contingent consideration in the table below) was calculated using a Black-Scholes model. See "Note 16—Fair Value" for further information on how the fair value of contingent consideration is determined.

Amortization expense of $6.0 million related to these intangible assets was recorded for the three months ended March 31, 2026. The entire value of goodwill was assigned to the Federal Solutions reporting unit and represents synergies expected to be realized from this business combination. $2.2 million of goodwill is deductible for tax purposes.

The amount of revenue generated by ATC and included within consolidated revenue is $39.8 million for the three months ended March 31, 2026. The Company has determined that the presentation of net income from the date of acquisition is impracticable due to the integration of general corporate functions upon acquisition.

The Company is still in the process of finalizing its valuation of the assets and liabilities acquired.

Supplemental Pro Forma Information (Unaudited)

The unaudited pro forma supplemental information is based on estimates and assumptions which the Company believes are reasonable and reflects the pro forma impact of additional amortization related to the fair value of acquired

intangible assets, the pro forma impact of interest expense on acquired debt, and the pro forma impact of reflecting acquisition costs, which consisted of legal, advisory and due diligence fees and expenses which are reflected in the earliest period presented. This supplemental pro forma information has been prepared for comparative purposes and does not purport to be indicative of what would have occurred had the acquisition been consummated during the periods for which pro forma information is presented.

Applied Sciences Consulting, Inc.

On October 1, 2025, the Company acquired a 100% ownership interest in Applied Sciences Consulting, Inc. ("ASC"), a privately owned company, for $28.2 million from cash on hand. ASC specializes in water and stormwater solutions for cities, counties, and water management districts across the state of Florida. ASC enhances our ability to partner with Florida communities on delivering innovative solutions for their resiliency challenges, while expanding those capabilities to new and existing clients around the world. In connection with this acquisition, the Company recognized $0.5 million of acquisition-related expenses in “Selling, general and administrative expense” in the consolidated statements of income for the year ended December 31, 2025, including legal fees, consulting fees, and other miscellaneous direct expenses associated with the acquisition.

Amortization expense of $0.4 million related to these intangible assets was recorded for the three months ended March 31, 2026. The entire value of goodwill was assigned to the Critical Infrastructure reporting unit and represents synergies expected to be realized from this business combination. The entire value of goodwill is deductible for tax purposes.

The amount of revenue generated by ASC and included within consolidated revenue is $2.4 million for the three months ended March 31, 2026. The Company has determined that the presentation of net income from the date of acquisition is impracticable due to the integration of general corporate functions upon acquisition.

The Company is still in the process of finalizing its valuation of the assets and liabilities acquired.

Supplemental Pro Forma Information (Unaudited)

The unaudited pro forma supplemental information is based on estimates and assumptions which the Company believes are reasonable and reflects the pro forma impact of additional amortization related to the fair value of acquired intangible assets, and the pro forma impact of reflecting acquisition costs, which consisted of legal, advisory and due diligence fees and expenses which are reflected in the earliest period presented. This supplemental pro forma information has been prepared for comparative purposes and does not purport to be indicative of what would have occurred had the acquisition been consummated during the periods for which pro forma information is presented.

Chesapeake Technology International, Corp

On June 30, 2025, the Company acquired a 100% ownership interest in Chesapeake Technology International, Corp ("CTI"), a privately owned company, for $91.5 million from cash on hand. CTI brings extensive capabilities as an all-domain technology solutions provider, powered by cutting-edge products that enhance the warfighters’ ability to sense, evaluate and deliver effects within the invisible battlespaces. CTI enhances our mission-ready solutions for the Department of War. In connection with this acquisition, the Company recognized $2.2 million of acquisition-related expenses in “Selling, general and administrative expense” in the consolidated statements of income for the year ended December 31, 2025, including legal fees, consulting fees, and other miscellaneous direct expenses associated with the acquisition.

Amortization expense of $1.4 million related to these intangible assets was recorded for the three months ended March 31, 2026. The entire value of goodwill was assigned to the Federal Solutions reporting unit and represents synergies expected to be realized from this business combination. $8.8 million of goodwill is deductible for tax purposes.

The amount of revenue generated by CTI and included within consolidated revenue is $17.7 million for the year ended March 31, 2026. The Company has determined that the presentation of net income from the date of acquisition is impracticable due to the integration of general corporate functions upon acquisition.

The Company is still in the process of finalizing its valuation of the assets and liabilities acquired.

Supplemental Pro Forma Information (Unaudited)

The unaudited pro forma supplemental information is based on estimates and assumptions which the Company believes are reasonable and reflects the pro forma impact of additional amortization related to the fair value of acquired intangible assets, and the pro forma impact of reflecting acquisition costs, which consisted of legal, advisory and due diligence fees and expenses which are reflected in the earliest period presented. This supplemental pro forma information has been prepared for comparative purposes and does not purport to be indicative of what would have occurred had the acquisition been consummated during the periods for which pro forma information is presented.

TRS Group, Inc.

On January 31, 2025, the Company acquired a 100% ownership interest in TRS Group, Inc. ("TRS"), a privately owned company, for $36.6 million from cash on hand (of which $3.8 million will be paid in July 2026). TRS is an environmental solutions firm that specializes in remediation technology. In connection with this acquisition, the Company recognized $0.5 million of acquisition-related expenses in “Selling, general and administrative expense” in the

consolidated statements of income for the year ended December 31, 2025, including legal fees, consulting fees, and other miscellaneous direct expenses associated with the acquisition.

Amortization expense of $0.4 million and $0.2 million related to these intangible assets was recorded for the three months ended March 31, 2026 and March 31, 2025, respectively. The entire value of goodwill was assigned to the Critical Infrastructure reporting unit and represents synergies expected to be realized from this business combination. The entire value of goodwill is deductible for tax purposes.

The amount of revenue generated by TRS and included within consolidated revenue is $4.1 million for the three months ended March 31, 2025. The Company has determined that the presentation of net income from the date of acquisition is impracticable due to the integration of general corporate functions upon acquisition.

Supplemental Pro Forma Information (Unaudited)

The unaudited pro forma supplemental information is based on estimates and assumptions which the Company believes are reasonable and reflects the pro forma impact of additional amortization related to the fair value of acquired intangible assets, and the pro forma impact of reflecting acquisition costs, which consisted of legal, advisory and due diligence fees and expenses which are reflected in the earliest period presented. This supplemental pro forma information

has been prepared for comparative purposes and does not purport to be indicative of what would have occurred had the acquisition been consummated during the periods for which pro forma information is presented.