Borrowing Costs Snap a Record M&A Streak, Pushing Q3 Deal Volume Below $1 Trillion

The global dealmaking surge that defined the first half of 2026 stalled hard in the third quarter. According to LSEG data cited by Reuters, global M&A totaled $993 billion in the three months through September, down 41% from the second quarter and the first quarterly reading under $1 trillion since Q2 2025.

The rate move is the cleanest explanation. The benchmark 10-year U.S. Treasury yield climbed from 4.44% to 5.29% over the same three-month stretch, according to analysis published by Kadenwood Capital citing LSEG data and Reuters. On October 1, the yield briefly touched 5.34%, its highest print since 2002. Financing an acquisition at those levels compresses the return math on most deals, and the megadeal count confirms it: only 10 transactions above $10 billion were announced in Q3, the fewest in any quarter since Q4 2024, according to LSEG data reported by Reuters.

Morgan Stanley's global head of M&A, John Collins, told Reuters that higher yields make valuations "sometimes a little tougher" at the margins, but stopped short of calling it a structural slowdown. Whether that caution holds into Q4 is the live question.

The Q3 retreat doesn't erase what was a historically strong year through June. LSEG said the first half reached an all-time high of $2.85 trillion, even as deal count fell to a six-year low, per data cited by Economy Middle East. That gap between value and volume is the story inside the story: capital concentrated into fewer, larger transactions while smaller deals dried up. Year-to-date global M&A still stood at $3.9 trillion through September, up 28% from the same period a year earlier and the highest for that span since 2001, according to LSEG data reported by Reuters and carried by RTÉ News.

The regional picture is uneven. The Q3 pullback was sharpest in the United States and Europe. Asia-Pacific ran the other direction: deal value there hit $242 billion in Q3, up 8% from Q2 and 36% year-over-year, according to LSEG data cited by Reuters. Private equity-backed M&A hit its strongest year-to-date value since records began in 1980, though Q3 alone slowed versus the prior year.

One pending deal that illustrates the regulatory, not just financial, friction in large transactions: Union Pacific's $85 billion proposed merger with Norfolk Southern remains under Surface Transportation Board review. As detailed in Union Pacific's Form 10-Q filed with the SEC for the quarter ended September 30, the STB accepted the railroads' revised application in May but placed all proceedings in abeyance pending supplemental filings. The board later resumed its schedule, with a projected timeline running through at least May 28, 2027, and a final decision due within 90 days after the record closes, per reporting by Sourcing Journal. Opposition filings from rival carriers, including BNSF and CSX, and from a coalition of nine state attorneys general, have added friction that could push a final ruling into late 2027.

Taken together, the Q3 numbers suggest the easy half of the M&A cycle is done. Cheap debt financed the record first half. At a 5%-plus 10-year yield, every deal model gets harder to close, and the board rooms that moved fast in January are moving slower now.

Sources cited:
- Reuters / LSEG data, as carried by RTÉ News (https://www.rte.ie/news/business/2026/1002/1593748-global-ma-deal-rush-fades-in-q3/)
- Economy Middle East (Reuters sourcing) (https://economymiddleeast.com/news/global-ma-falls-41-percent-to-993-billion-in-q3-as-borrowing-costs-bite-while-2026-deal-value-still-reaches-3-9-trillion/)
- Kadenwood Capital (LSEG / Reuters primary) (https://kadenwoodcapital.com/perspectives/below-a-trillion-above-five-percent)
- Union Pacific Corp, Form 10-Q (Q3 FY2026), SEC EDGAR (https://www.sec.gov/Archives/edgar/data/0000100885/000010088526000321/unp-20260930.htm)
- Sourcing Journal (WWD) (https://wwd.com/sourcing-journal/logistics/union-pacific-norfolk-southern-merger-stb-review-resumes-rail-1239143795/)
- Global Banking & Finance Review (Reuters sourcing) (https://www.globalbankingandfinance.com/global-m-deal-rush-fades-third-quarter-rising-borrowing/)