Charlesbank's $700m WSHB deal tests the last wall keeping private equity out of law

Charlesbank reportedly plans to take a stake in a new entity that houses WSHB’s back office and other non-legal operations, known as a management services organisation, or MSO.

The structure splits a firm in two: an attorney-owned entity that provides legal advice, and an MSO that holds the remaining assets and supplies services to the lawyers in return for sizeable fees. That separation lets private equity bypass professional ethics rules, which bar non-lawyer ownership of law firms in most US states. According to the FT, the pitch materials contemplated a “majority sale of the entity,” although the exact size of Charlesbank’s stake could not be established.

The Boston-based firm, which manages around $24bn in assets, deployed a similar structure two years ago to buy accounting firm Aprio, and it is now widening its professional services portfolio. Aprio itself used capital from that deal to acquire other accountancies and to enter the legal market through an Arizona scheme that permits non-attorney ownership of law firms.

WSHB makes for an attractive target. Founded in 1997 and based in Los Angeles, the firm has more than 550 lawyers who defend companies against product liability, personal injury, and other claims, operating from 43 offices across 35 states, with a presence in the London insurance market.

The business generated $244.4m of revenue in 2025, up almost 20%, and has expanded at roughly 20% a year over three years, according to PitchBook, which cited a memorandum prepared for the sale. The same document valued the deal at about 18 times the firm’s 2025 adjusted earnings of $38.2m.

WSHB told prospective buyers that a wave of funding from private equity and litigation finance groups had turbocharged personal injury and other liability claims, leaving more defence work than the firm could take on unaided. With Charlesbank’s backing, it wants to recruit teams from rival firms and expand internationally, including across Central and South America. The capital would also allow WSHB’s four owners to fund growth beyond their own means and to hand equity to senior attorneys, PitchBook reported.

WSHB ran an auction through Los Angeles-based Riverbrook Capital, while Charlesbank is advised by Piper Sandler. The firms have signed a letter of intent, and a definitive agreement is expected in the coming weeks.

Over the past year, large firms including Quinn Emanuel, McDermott Will & Schulte, and Paul Weiss have spoken to private equity groups or bankers about the MSO idea, and the structure is increasingly used to acquire personal injury practices and to launch AI-enabled legal start-ups. Insurance-defence peer Tyson & Mendes is also seeking private equity investment, according to PitchBook.

The approach carries real risk, however. MSOs have not been widely tested against US legal ethics rules, which are designed to stop commercial pressures from tainting advice to clients, and that uncertainty has made some firm owners and investors cautious. Proponents counter that, structured properly, the model keeps private equity owners away from case decisions while freeing lawyers to focus on clients rather than administration.