Books of Business Under the Spotlight in Major Lateral Moves

Portability of clients is often clear within the first year: if matters have not followed promptly or if clients have not swiftly given new mandates, then it is unlikely to happen, writes a recruitment consultant.

Originally published on Law.com International on October 23, 2025.

Lateral hiring has long been an important part of law firms’ growth strategies but there has never been as much movement in the market as there is now. Most major firms no longer have the patience to focus purely on organic growth. The few firms that do only hire lateral partners when they lack the skillset that that partner brings.

When lateral hiring is a tool for revenue growth, assessing the size and portability of the book of business from an incoming partner becomes crucial. We see hiring firms do key-clients conflict checks very early on in the process, sometimes directly after the first or second meeting. There is no point in wasting valuable time and resources on a process if there is a deal-breaking conflict to be discovered down the line.

Many hiring firms will go to great length to minimise the uncertainty. They will check references, including client references, and hire third parties to carry out due diligence on partner candidates.

Firms ask candidates to fill in detailed lateral partner questionnaires and then dissect their answers. We observe hiring firms drilling down into size of the portable book of business, with some firms assuming in principle that a certain percentage will not follow. Firms are officially coy about such assumptions; but we hear that some firms will assume that 30% of matters and clients will not follow, even if the incoming partner feels confident that they will.

Firms quiz candidates about the nature of their relationship with each stated portable client. Recently a cautious partner had assessed the portability of faithful long-standing client at 90%, prompting the hiring firm’s business development team to ask them “why only 90%?” “Because you never know”, answered the candidate!

Portability of clients is often clear within the first year: if matters have not followed promptly or if clients have not swiftly given new mandates, then it is unlikely to happen. However, when a partner talks about bringing some form of team, then optimism in the new firm tends to rise.

The ‘team’ could be anything from a partner telling the hiring firm that more junior lawyers will want to join, or two (or more) partners moving together. Team moves can be tricky because of restrictive covenants but they have the advantage of signalling in a very concrete way that the key partner believes they can keep themselves and their team busy. It also shows the firm that the lateral needs a team to do the work. And finally, a team move may ensure that clients will follow, which indeed, they most likely will do if nobody is left behind at the old firm to handle the matters of the moving partner.

While most firms will go to great length to ascertain the size of the portable book, we occasionally see firms assuming that the lateral partner will not bring any work with them. As one firm chair put it, any portable business is “gravy.” One would be foolish to mistake that for lower standards. The test there is all about track record and cultural fit: what did that partner do at their previous firm and what will that partner achieve on the new platform?

Be it a filling main course of many new clients or deals or just ‘gravy’, firms’ appetite for lateral hiring will remain strong.