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Global M&A activity surges 49% in 2025 as megadeals reshape the dealmaking landscape
LSEG data shows full-year M&A volume hit $4.6 trillion, the strongest annual performance since 2021, driven by a wave of transactions valued above $10 billion.
Global mergers and acquisitions activity hasn’t looked this aggressive since the post-pandemic dealmaking frenzy. Full-year 2025 M&A volume reached $4.6 trillion according to LSEG’s Deals Intelligence platform, a 49% jump from 2024 and the highest annual total since 2021.
The engine behind the surge isn’t more deals. It’s bigger ones. Megadeals valued above $10 billion have returned with force, pushing aggregate values skyward even as the total number of transactions trended lower.
Q3 momentum and the megadeal machine
The third quarter of 2025 delivered roughly $1.1 trillion in announced M&A volume, a 13% sequential increase from Q2 2025.
Year-to-date M&A value through Q3 climbed approximately 33%, reinforcing the broader trend. But the numbers tell a split story: while dollar values soared, deal counts actually drifted downward.
The small-deal drought and what it signals
The flip side of the megadeal boom is a quieter market for mid-sized and smaller transactions. Deal counts trending downward even as values surge suggests that middle-market M&A hasn’t participated equally in the recovery.
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This creates a bifurcated market. At the top end, competition for premium assets is fierce and valuations reflect it. Below that tier, sellers may find fewer bidders and longer timelines to close.
Investment banks have felt this split in their advisory revenue. Firms with relationships to large-cap clients have posted strong fee income, while those more dependent on mid-market deal flow have seen less uplift from the headline numbers.
LSEG’s data, which tracks announced deal values globally, captures this dynamic clearly. The platform has become one of the most widely referenced sources for M&A statistics in financial media and institutional research, giving its quarterly snapshots outsized influence on how the market interprets dealmaking trends.
Stock volatility around large deal announcements remains a feature, not a bug, of this landscape. Target companies can see shares jump 20% or more on news of an acquisition, while acquirer stocks often face initial pressure as markets assess whether the premium paid is justified.
The concentration of activity in megadeals also means that a single broken transaction, whether due to regulatory intervention, financing issues, or buyer’s remorse, can materially shift quarterly statistics. That makes the headline numbers somewhat fragile, dependent on a relatively small number of very large outcomes.