The U.S. upstream mergers and acquisitions market staged a rebound in the fourth quarter of 2025, registering $23.5 billion in announced transactions and bringing total deal value for the year to $65 billion, according to analytics firm Enverus.
After a mid-year slowdown, dealmaking accelerated as buyers that had pulled back earlier in the year renewed activity. Enverus attributed the rebound to a combination of motivated buyers, including refunded private equity teams, wider adoption of securitized financing structures and new international entrants entering the competitive U.S. upstream landscape.
International participation in U.S. upstream deals reached a seven-year peak in 2025 at $7.4 billion, with approximately $6 billion of that activity occurring in the fourth quarter. These foreign buyers concentrated their purchases on assets in the Gulf of Mexico and in the Denver-Julesburg Basin.
One transaction highlighted by Enverus was Mitsubishi’s $7.5 billion purchase of Aethon Energy’s U.S. shale production and infrastructure, a deal that shifted international focus toward core Haynesville holdings and underscored global interest in Gulf Coast gas. As opportunities in Haynesville become more constrained, Enverus said buyers are likely to look elsewhere for gas exposure, naming Eagle Ford and the Anadarko Basin as alternative targets.
The fourth quarter also featured stronger activity outside the Permian Basin, a pattern that occurred alongside rising Gulf Coast gas prices and steady conditions in Appalachia. Deal activity outside the Permian was a notable component of the quarter’s pickup.
The biggest transaction of the fourth quarter was the merger of SM Energy and Civitas Resources, a combination that included material positions in both the Permian Basin and the Denver-Julesburg Basin. Enverus also noted another prominent 2025 consolidation involving Crescent Energy and Vital Energy.
Looking forward, Enverus expects the upstream M&A market to remain active in 2026. The firm pointed to continuing support from private capital, buyers backed by asset-backed securitization (ABS), and sustained international interest as key factors that could underpin deal flow in the coming year.
Clear summary: Enverus reports that U.S. upstream M&A recovered in Q4 2025 with $23.5 billion in announced deals, bringing full-year totals to $65 billion. The rebound was driven by returning private equity buyers, greater use of securitized financing, and strong international participation, particularly focused on Gulf Coast gas and select basins.