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 [1]. This claim is backed by its earlier acquisition terms—US$550 million in cash for Greenhill, with the brand and leadership preserved [7]. Its banking division, now bolstered by more than 370 Greenhill staff plus prior acquisitions like Capstone Partners, has expanded its global advisory bandwidth significantly [3][7].

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 [2][3]. Industrials, communication services, and IT sectors are particularly strong. Though outbound volume dropped, when deals transpire they are larger and more cross-border [2][3].

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 [5]. Enhanced foreign investment screening legislation (to be revised in 2026) may pose challenges in certain sectors, but also offers clarity over strategic thresholds [4].

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 [1][6]. 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.