Guide · For firm leadership
The partners leave at the announcement, not at the close.
A merger vote prices the combined firm. The partners price it too, and most of them do it in the weeks between the announcement and the first day of the new letterhead. Retention terms written after the close address the partners who stayed.
What does a merger do to the partners it was meant to combine?
The published evidence is thin and points one way. Partners leave early, the terms firms rely on to hold them are the least tested, and the one retention statistic everyone borrows was measured on a different group of lawyers.
- 17+
- partners left one New York firm after its merger was announcedbefore the combined letterhead existed
- Above the Law, 9 February 2026
- 30–38%
- of lateral partners leave within five yearsa lateral population, not a merger population
- Decipher via Passle, restated by Above the Law, May 2026
- 43
- U.S.-connected combinations completed in the first half of 202659 completed in full-year 2025
- Fairfax Associates, note of 1 July 2026
- $5.8M
- combined clawback now being tested in the Southern District of New Yorkcomplaint filed 29 June 2026; pending
- ABA Journal, 7 July 2026
Fairfax Associates counted 59 U.S.-connected law firm combinations completed in 2025 and 43 in the first half of 2026. Every one of them is a retention event for the partners of the smaller firm and, less often acknowledged, for the partners of the larger one. The dated list of 2026 closes, with the talent each one moved, is on the law firm mergers 2026 page. This guide takes the firm leader’s side of those closes: what the partners do, what the tools are, and where the evidence runs out.
The exits are scheduled by the announcement, not by the close.
A merger is announced, voted, regulated and then closed. Partners with portable books read the first step as the decision point.
Above the Law reported on 9 February 2026 that at least 17 partners had left one New York firm since its merger announcement. The same day, Reuters recorded five of that firm’s litigation partners joining another firm’s New York bench, citing a plaintiff-and-defendant conflict on antitrust matters created by the combination. The departures were not a reaction to the integration. The integration had not happened yet.
That timing matters for the firm leader. A retention plan built around the first day of the combined firm starts after the partners with the most portable books have had their conversations. The sequence that fits the evidence runs the other way: map the partners whose books are portable, decide who the firm must keep, and have the conversation before the vote, not after.
The five-year data describe the same instinct at lower volume. Decipher Investigative Intelligence research, cited in a Passle report and restated by Above the Law in May 2026, puts lateral-partner departures at 30 to 38 percent within five years, and reports that 90 percent of firms have business development challenges with laterals. SurePoint’s 2025 State of the Legal Industry Report found 76 percent of Am Law 200 equity-seat hires made from 2015 to 2022 still at their firm after three years. Those are ordinary lateral hires into a stable firm. Partners who are brought in by a merger did not choose the new letterhead, and there is no reason to expect them to be stickier.
The five-year retention levers for individual laterals are set out in how law firms retain lateral partners. The merger case adds one variable: the partner is deciding while the firm is distracted by the transaction.
A retention plan that starts on the first day of the combined firm is talking to the partners who stayed.
Clawbacks are the standard tool, and New York is narrowing them.
Forgivable loans, deferred compensation and withdrawal payments keep partners in their seats. Whether they survive a challenge is now a live legal question.
NYC Bar Formal Opinion 2025-3, issued on 13 August 2025, reads compensation terms that, by their terms or in practice, discourage a lawyer from leaving to compete as a problem under New York Rule 5.6(a). The opinion applies the older Cohen v. Lord, Day & Lord and Denburg v. Parker Chapin line. Uniform stay-through-date terms that apply whether a lawyer goes in-house, to government or to a competitor are more defensible than discretion that is used to punish a competing move.
The test case is pending. On 29 June 2026, two former partners of a London-headquartered firm filed in the Southern District of New York. They seek a declaration that New York law, not English law, governs a combined clawback of $5,797,619, about $5.8 million, after they joined another firm. The ABA Journal reported the complaint on 7 July 2026. It is a complaint, not a ruling.
For a firm leader, three points follow. First, terms drafted for a merger should be written to apply equally to every departure route, because selective enforcement is the weakest position under Opinion 2025-3. Second, the governing-law clause is part of the retention design, and a choice of English law for a New York seat is now a litigated risk. Third, a clawback that holds a partner who wants to leave also holds the partner’s clients in a relationship with a lawyer who is looking elsewhere. It buys time, not commitment.
Some partners cannot stay, whatever the retention terms say.
A merger unions two client lists. Partners on the wrong side of that union leave because the rules require it.
New York Rule 1.10(c), at 22 NYCRR 1200.1.10 and in force since 1 January 2025, lets a firm screen most laterals. It does not let screening prevent imputation where the lateral substantially participated in the management and direction of a litigation, arbitration or other adjudicative matter. Only a waiver from the former client cures it. NYC Bar Formal Opinion 2026-1, dated 30 July 2026, sets out the notice and screen mechanics for the laterals who can be screened: notice within a couple of weeks of joining and a screen in place immediately.
The five-partner litigation exit reported on 9 February 2026 fits that pattern. The partners ran plaintiff-side antitrust work and the incoming firm already represented a defendant. No retention package changes that. Firm leaders who run the conflicts union before the vote know which benches are at risk and can plan the rebuild instead of discovering it in the first month.
The buyer’s side of the same problem, what a company’s general counsel should ask before an incoming book closes, is in lateral partner due diligence. The hiring side of the rebuild is the work of partner recruiting.
Nobody publishes the number a firm leader needs, including us.
The figure that would settle this argument is the share of partners who leave within two years of a merger closing. It does not exist in public.
Fairfax counts completed combinations, not people. Decipher and SurePoint measure laterals. Above the Law reports named exits one firm at a time. Put together, they show that exits happen early, that five-year lateral attrition runs at a third, and that the tools firms use are contested. They do not show the merger attrition rate.
Sartori & Partners has no such series either. The firm’s research programme maps more than 1,480,000 lawyers, has run a quarterly survey since 2019 and holds 2,600+ partner conversations since 2017. The published law-firm file is a single Houston energy lateral, a conflict-cleared hire from a mapped field of 340 partners within 633 practitioners, and its outcome is described qualitatively: the hire stayed. The 97 percent twelve-month and 91 percent twenty-four-month retention figures published on the firm fact sheet cover 400+ placements since 2017 (230+ in-house). They describe in-house leaders, not partners, and they should not be quoted as a law-firm benchmark. A firm leader who hears that number in a pitch for partner retention is hearing the wrong book.
That gap is the honest answer to the query. The defensible claims are narrower than the confident ones: partners leave early, the terms that hold them are being tested, and the rules on conflicts remove some of them whatever the firm does.
Seven documents a leadership team should hold before the vote.
The list below is built from the exits and the rules above. It is a sequence, not a scorecard.
| Document | What leadership asks | When | Owner |
|---|---|---|---|
| Partner map by book and by matter | Which partners run adjudicative matters adverse to the other firm’s clients? Those are the Rule 1.10(c) walks. | Before announcement | Managing partner + general counsel |
| Client-facing statement | What does the top client hear, and from whom, in the first week? A partner who learns the news from a client has already taken a call. | Announcement day | Chair + practice heads |
| Retention terms | Stay-through dates, deferred pay and clawbacks, written to apply the same way whether the partner goes in-house, to government or to a competitor. | Announcement to vote | Compensation committee |
| Pay and title parity | Which partners move to a different lockstep, tier or title? Sterling and dollar scales that do not unify need an on-record explanation. | Before the vote | Finance + compensation |
| Conflicts union | Both client lists unioned, advance waivers re-read against the larger map, and the post-close notice calendar written. | Vote to close | Office of the general counsel |
| Rebuild plan | Which benches leave in numbers, and which seats are filled from outside? Hiring into a depleted team starts before the close, not after. | Announcement onward | Practice heads + recruiting |
| Named sponsor for month 4 to 18 | Retention is decided at the second client introduction, not at the welcome lunch. A sponsor with dates, not a title. | Day one of the letterhead | Practice heads |
Two rows carry most of the risk. The partner map comes first because every later step depends on knowing whose book is portable and whose matters cannot be screened. The rebuild plan comes next because the benches that leave in numbers have to be refilled from outside, and a search for a practice-group team started after the close competes with every other firm that watched the same exits. Outside hiring for a depleted bench is where retained partner search is used, and the lead time starts at the announcement.
What firm leaders ask about merger partner retention
What happens to partners after a law firm merger?
Most of the loss happens before the close, not after. Above the Law reported on 9 February 2026 that at least 17 partners had left one New York firm since its merger was announced in December 2025, including a five-partner litigation team. Fairfax Associates counted 43 U.S.-connected combinations completed in the first half of 2026. No public series measures post-close partner attrition across all of them, and Sartori does not publish one.
Are partner clawbacks enforceable in a law firm merger?
It depends on the terms and the governing law, and the test case is pending. NYC Bar Formal Opinion 2025-3, issued 13 August 2025, treats compensation terms that discourage a lawyer from leaving to compete as a Rule 5.6(a) problem. A complaint filed in the Southern District of New York on 29 June 2026 seeks a declaration that New York law, not English law, governs a clawback of about $5.8 million. That complaint is not a holding.
What percentage of lateral partners leave within five years?
Decipher Investigative Intelligence research, cited in a Passle report and restated by Above the Law in May 2026, puts it at 30 to 38 percent. SurePoint’s 2025 report found 76 percent of Am Law 200 equity-seat hires from 2015 to 2022 still at their firm after three years. Neither number isolates partners who joined through a merger.
Can a screen keep a litigation partner on a merged New York letterhead?
Not if the partner substantially ran the adjudicative matter. New York Rule 1.10(c), at 22 NYCRR 1200.1.10 and in force since 1 January 2025, does not let screening prevent imputation in that case. Only a waiver from the former client does. NYC Bar Formal Opinion 2026-1, dated 30 July 2026, sets out the notice and screen mechanics for other laterals.
When should a merging firm start retaining its partners?
At announcement. The exits reported in 2026 began within weeks of the December 2025 announcement and ran to the July close. A retention file that starts on day one of the combined letterhead is addressing the partners who stayed, not the ones who had already gone. Partner recruiting for the receiving side and the rebuilt side runs on the same calendar.
Does Sartori publish a merger partner retention rate?
No. The published Sartori law-firm file is one conflict-cleared Houston energy lateral drawn from a mapped field of 340 partners, and its outcome is qualitative. The 97 percent twelve-month and 91 percent twenty-four-month retention rates belong to 400+ placements since 2017 (230+ in-house). They are a different population and are not used as a partner figure here.
Bar opinions, court filings, press reports and deal censuses.
The conflicts and clawback material is the New York rule and the bar opinions. Volume comes from Fairfax. Departure rates come from Decipher and SurePoint. Named exits come from press reports.
Sources
12 references- Sartori & Partners — Research Programme sartoriglobal.com ↗
- Sartori & Partners — About sartoriglobal.com ↗
- Case study — Confidential lateral partner, Houston energy sartoriglobal.com ↗
- Above the Law — A Third Of Lateral Partners Are Gone In 5 Years (May 2026) abovethelaw.com ↗
- Above the Law — Cadwalader Litigation Leaders Exit Amid Hogan Lovells Merger Fallout (9 February 2026) abovethelaw.com ↗
- Reuters — Cadwalader litigation leaders jump to Mintz ahead of Hogan Lovells merger (9 February 2026) reuters.com ↗
- Fairfax Associates — Q2 2026 merger note (1 July 2026) fairfaxassociates.com ↗
- SurePoint — 2025 State of the Legal Industry Report surepoint.com ↗
- NYC Bar — Formal Opinion 2025-3 (13 August 2025) nycbar.org ↗
- ABA Journal — 2 former partners sue over alleged compensation clawbacks (7 July 2026) abajournal.com ↗
- 22 NYCRR 1200.1.10 — Imputation of conflicts of interest law.cornell.edu ↗
- NYC Bar — Formal Opinion 2026-1 (30 July 2026) nycbar.org ↗
Fairfax counts completed combinations, not people. Decipher and SurePoint measure laterals, not merged partners. The clawback complaint is pending and is not a holding.
There is no published post-merger partner attrition rate, and this guide does not estimate one. Sartori figures on this page are limited to those published on the research page, the firm fact sheet and the case studies.
The same events, from three sides.
The 2026 close list, the lateral retention levers and the buyer’s conflicts file sit beside this guide.
Law Firm Mergers 2026: the close dates, and the talent each one moves
The dated 2026 list of combinations and what each close did to the talent a company can still instruct.
Read the 2026 listHow Law Firms Retain Lateral Partners
The five-year departure band and the levers a managing partner can assign: book transfer, a sponsor, a rate test.
Read the retention leversLateral Partner Due Diligence
The same events from the buyer’s side: the conflicts file a general counsel should see before an incoming hire closes.
Read the buyer’s fileFor managing partners and firm chairs
Rebuilding a bench after an announcement?
We run retained partner searches for firms that have lost a practice team or are preparing for a combination: conflicts checked first, portability verified before any introduction.