Activist Funds Push Back on M&A with Lawsuits and Proxies

Activist hedge funds are increasingly opposing proposed mergers and acquisitions worldwide, using litigation, proxy fights and public campaigns to challenge deals they view as undervaluing targets or exposing shareholders to integration and financing risks.

Fund managers that previously pressed companies to pursue sales, breakups or strategic reviews are more often taking positions against announced transactions. Event-driven investors are allocating capital either to support or to oppose deals depending on where they see the best opportunity for returns.

The trend accelerated in the second half of 2025. Barclays data shows more than half of activist campaigns launched in that period included demands tied to mergers, acquisitions or other corporate transactions. A renewed surge in global dealmaking has produced a larger pipeline of transactions open to investor challenge.

Activists use a range of tactics. Litigation is deployed to block or delay approvals by highlighting procedural or disclosure weaknesses. Proxy contests seek to change board votes or replace directors who back a deal. Public campaigns aim to persuade other shareholders and exert pressure on target and acquirer management and advisers.

Activists raise specific objections. Some push for higher bids or alternative buyers when they judge the price too low. Others identify integration, financing or governance risks and seek changes to transaction structure, supplemental financial disclosures or protections for minority shareholders.

Investment banks and corporate legal teams have adjusted deal processes. Boards are engaging advisers earlier, preparing engagement plans with potential compromises such as go-shop provisions, changes to break fees and additional disclosures intended to reduce legal exposure. Some companies have revised offers or added shareholder protections to try to limit opposition.

Market participants and advisers expect merger-arbitrage and activist funds to remain active in contested transactions through 2026. The presence of both supportive arbitrage positions and oppositional activist campaigns has coincided with more contested negotiating environments and, in some cases, longer timelines for deal approval and completion.