Mizuho’s Greenhill Buyout Powers Japan-US M&A Surge: Strategy, Risks & Opportunity

Mizuho’s CEO, Masahiro Kihara, has signaled that the firm has passed a major inflection point: with Greenhill hanging its advice platform in the U.S., Mizuho claims to be “now able to pursue large-scale M&A deals” in both the U.S. and Japan. This claim is backed by its earlier acquisition terms—US$550 million in cash for Greenhill, with the brand and leadership preserved. Its banking division, now bolstered by more than 370 Greenhill staff plus prior acquisitions like Capstone Partners, has expanded its global advisory bandwidth significantly.

These moves align with broader market dynamics. Japan’s M&A market has seen a sharp rise in value, especially in H1 2025, where domestic and inbound M&A totals rose to about US$232 billion—more than triple the same period a year prior. Outbound deal value also surged (~87%) through Q3 2025, though deal count has slightly declined. Industrials, communication services, and IT sectors are particularly strong. Though outbound volume dropped, when deals transpire they are larger and more cross-border.

Regulatory and policy developments are providing tailwinds: Prime Minister Takaichi’s pro-growth agenda has emphasized stimulus, tax credits, and business enabling reforms, while the BOJ is reworking interest rate policy, likely to hike rates, which impacts funding and deal feasibility. Enhanced foreign investment screening legislation (to be revised in 2026) may pose challenges in certain sectors, but also offers clarity over strategic thresholds.

Strategically, Mizuho is placing bets on advisory, sector specialization (clean energy, renewables), talent acquisition (senior hires in EMEA), and leveraging Greenhill’s advisory heritage to compete with bulge-bracket banks globally. However, key open questions remain: whether valuation gaps will limit deal flow (especially cross-border), how regulatory/sovereign risk (e.g. security reviews, trade policy) will affect deal completion, and whether macro pressures—such as bond market stress, yen volatility, inflation—may undercut momentum.