Insurance M&A Counsel in 2026: Two Top-10 Lists, One Shared Firm

A general counsel at an insurer who searches for insurance M&A law firms will find two short lists that hardly touch. Sartori & Partners data show 802 insurance deals on record in the 12 months to October 2026, against 11,230 corporate and M&A deals across every sector. The ten firms with the most insurance deals and the ten with the most corporate and M&A deals have a single firm in common. Corporate and M&A lawyers worked on 25.2% of the sector's deals, which puts them third among its benches. For a company about to hire deal counsel, the practical question is which list to start from, and what each one leaves out.

Set the two firm lists side by side and count name by name. Of the ten firms with the most insurance deals, only Latham & Watkins also appears among the ten with the most corporate and M&A deals. It ranks 9th on the insurance list, in the 11-20 band of deals, and first on the corporate list, in the 401-700 band. Neither list is a ranking for insurance M&A. The insurance list counts every deal in the sector, disputes and capital markets work included. The corporate list counts every deal the practice handled, in any sector. No list is published for the pair itself, and a firm missing from one list tells you nothing about its work there.

The bands show the gap in scale. The firm first on the insurance list, Skadden, Arps, Slate, Meagher & Flom LLP & Affiliates, sits in the 41-60 band; the corporate list opens in the 401-700 band. The sector is a small slice of the practice, so practice volume and sector volume measure different things. A shortlist drawn from one list alone will either miss insurance depth or miss transactional volume. Start from both, then ask each firm to name the insurance M&A matters its proposed team ran.

Insurance and reinsurance lawyers worked on 29.9% of insurance deals, capital markets lawyers on 27.1% and corporate and M&A lawyers on 25.2%. Across all deals on record, the corporate share is 23.3%, so the sector uses corporate lawyers about as often as the market does. The specialist bench is what sets insurance apart: insurance and reinsurance lawyers sit on 0.7% of all deals. One deal can carry several practices, and some carry no practice label, so these shares overlap and are never added. In practice, an insurer's acquisition rarely stays with corporate lawyers alone. Expect the file to involve an insurance and reinsurance specialist, and ask at the pitch who leads when both sit on it.

Deal size widens the distance between the lists. Where a value was disclosed, on 20.4% of insurance deals, the median was US$750 million. Corporate and M&A deals with a disclosed value, 17.7% of the practice's deals, had a median of US$315 million. The insurance median is 2.4 times the corporate one. Both rest on a minority of deals, so they describe the disclosed part of each market, not every mandate. Mix matters here too: M&A was 24.4% of insurance deals by type, against 19.3% of all deals, while disputes and investigations were 30.2%. For an insurer, a larger typical ticket means a deeper team on the file: check that the corporate partner has run deals of that size, not only deals in the sector.

Year on year, the insurance deal count held flat (+1.3%), at 793 deals in the latest settled 12 months against 783 a year before. Over the same windows the corporate and M&A deal count rose 9.5%, at 11,170 against 10,198, and the whole deal market rose 10.6%. In the Sartori & Partners lateral database, the practice's own hiring moved with the practice: corporate and M&A lateral moves rose 15.8%, at 2,933 against 2,532. Those are lawyers changing firms, not deals, and they sit beside the insurance count without explaining it. The consequence for a buyer: corporate partners are busier on other sectors' work than a year ago, so the named team on an insurance mandate should be confirmed early and written into the engagement terms.

Lawyers in New York worked on 40.2% of insurance deals with a known lawyer location, and lawyers in London on 22.9%. Washington followed at 13.6% and Chicago at 10.7%. Continental Europe appears further down, with Paris at 3.9% and Frankfurt at 3.6%. A deal counts in every city where its lawyers worked, so these shares overlap; they show where the work is done, not where lawyers are counted. An insurer with a cross-border transaction should test the London bench of any firm on the shortlist as closely as the New York one.

First, do not rely on one list. With a single firm, Latham & Watkins, on both top-10 lists, sector volume and practice volume point to different firms; build the shortlist from both and ask for named insurance transactions. Second, staff the specialist next to the corporate lawyer: insurance and reinsurance lawyers sit on 29.9% of the sector's deals. Third, budget for size: the disclosed median runs at 2.4 times the practice's. Sartori & Partners track these figures from public law-firm announcements, firm websites and professional profiles, checked monthly, and the next edition will show whether the steady insurance count starts to follow the practice.