The Hidden Cost of Losing a Partner in a Professional Services Firm
When a partner leaves, the cost reaches beyond recruitment and lost fees. Drawing on episode 1 of The Value Conversation and published research, this article sets out the costs firms often miss and what reduces the risk.
When a partner leaves, some of the cost is plain to see. There's a recruiter's fee to pay, clients who may follow the partner, and a period before someone new is up to speed. Other costs take longer to appear, and they can be larger. Few organisations measure them. In the CIPD's 2024 survey of UK organisations, only 31% of respondents who knew their turnover data said their organisation calculates what turnover costs.
In episode 1 of The Value Conversation, David Whitson-Black explained why succession planning is about business continuity, not an HR exercise. He described it as "something that's really going to help support where your business needs to go." In his view, it starts with knowing where a firm depends on one person. That includes the people who build and maintain client relationships, and the knowledge, leadership and expertise that "when someone leaves can disappear with them." David also warned that "that future can come quickly in some cases."
At Weil, Gotshal & Manges LLP, it did. On 28 October, the management committee of the New York law firm recommended that it wind down, after more than 30 partners left this year. Partners are expected to vote on the plan. Reporting points to a loss of confidence in the firm's future, including a faltering succession at the top. The Wall Street Journal reports the firm has no debt.
Departures on that scale are rare. Most firms will lose a partner at some point, through retirement or a move to another firm. The rest of this article looks at what that costs, including the costs that are harder to see.
The costs David describes
David named several costs that add up when someone leaves. Recruitment comes first, whether the firm pays an agency or uses its own recruiters' time. Productivity drops from the day someone hands in their notice until a replacement joins. A partner also commands high rates and has a number of clients who could be affected. David also pointed to "the cost of developing other people" when no one is ready to take on the role.
He also asked whether the people who stay know the partner's clients, and whether they can give them the same service and support. When people lose a leader who supported them, he says, they can become disengaged or uncertain. The firm then risks losing them too.
Every firm's figures will be different. In David's view, "the research and data tells you that it is significant."
Costs that are easier to see
Most published evidence on the cost of losing a partner covers recruitment, the clients who follow and the colleagues who move with the partner. Much of it comes from US law.
Recruiting a replacement. BCG Attorney Search, a US legal recruiter, puts recruiter fees at around 20% to 25% of a new hire's annual base pay. For a partner in a UK mid-sized law firm, where average profit per equity partner is £334,000, that would be about £67,000 to £84,000.
Clients who follow. How many follow depends on the client and on how the relationship is held. In BTI Consulting's research with US corporate counsel, about one in five said they planned to, or were likely to, follow a partner who moved firms. Acritas surveyed more than 800 general counsel and found 73% of those whose key partner had left stayed with the firm. A study of about 6,000 clients of Texas lobbying firms also found most stayed with the firm when their lobbyist left.
Colleagues who leave with the partner. Partners often move in groups. In Thomson Reuters' 2023 research, 59% of lateral partners moved as part of a team.
Getting someone new up to speed. Oxford Economics found in 2014 that replacing a worker cost around £39,000 to £40,000 in UK legal and accountancy firms. Most of that cost was output lost while the new person got up to speed, and accountants took 32 weeks on average to reach full productivity. These figures cover people below partner level.
Costs that are harder to see
Fewer studies cover these costs. Where we found no published figure, we say so.
The time a new partner takes to perform. A partner hired from another firm takes about two to three years to come up to speed and for the firm to recover its investment. That comes from an ALM study of lateral partners hired by 100 leading US law firms between 2011 and 2016, which also found 47% left within five years. Citi Hildebrandt reported in 2015 that only 54% of lateral partners reached break-even five years after joining. Clients also move more slowly than partners expect. In Acritas research reported in 2018, partners expected about 70% of their client work to follow them, and 27% did. We found no comparable figures for accounting firms, or for the UK and Ireland.
Developing a successor. Promoting from within has its own costs. These include training and coaching, the time senior partners spend preparing a successor, and the months when colleagues cover the role. We found no published figure for them. David's advice is to start succession planning "as early on as possible".
Colleagues who leave later. John Morley, a law professor at Yale, reviewed 37 large law firm collapses. He found the decline usually began when a senior rainmaker left with a group of partners and associates. Because partners share the profits, each departure reduces the pay of those who remain and gives others a reason to go. A study of 676 Dutch accounting firms between 1880 and 1986 found the risk of a firm dissolving was highest when partners left together to set up a new firm nearby. That study counted mergers as well as closures. We found no study inside law or accounting firms of how staff respond when a partner leaves. Studies in other industries find people are more likely to leave after a leader or colleagues have gone.
The effect on the team. Partners often lead and support the people around them. O'Rielly & Roche, a US law firm that advises on partner departures, says departures can "foster uncertainty for those who remain, and damage morale." It adds that associates and staff "can view partner departures as a sign that the firm is unstable". David describes the same effect.
Knowledge that leaves. A partner carries knowledge the firm's systems may not hold, such as the reasoning behind past advice and who really decides at the client. IRIS, a document management vendor, puts it this way. "The agreements are still there, but the reasoning behind them is not."
Disruption for clients. In BTI's research, 48% of clients said a partner moving firms disrupts their operations. One general counsel said it would "add at least 15% to my budget".
Partners' time and fixed costs. Remaining partners spend time reassuring and serving the departing partner's clients. Rent, systems and support costs continue while fees fall, and the firm may need to repay the partner's capital. We found no published figures for these, and every firm can estimate its own.
Value at sale. Buyers take this risk into account. In UK accountancy practice sales, buyers commonly hold back part of the price until they see how many clients stay. One buyer pays 50% on completion and the rest over two years, reduced if retained fees fall below 85%. In the US, David Perez, chief executive of Tax Maverick AI, wrote in Accounting Today that dependence on the owner is "one of the largest discounts" in small and midsized deals.
An estimate
No one has published a measured estimate of the full cost of losing a partner in accounting or law, and our Five Forces Analysis 2026 found none. The table below brings published figures together into an estimate. It uses one assumption of our own, set out underneath.
How it is worked out | Partner in a UK mid-sized law firm | Partner in a UK mid-tier accountancy firm | |
|---|---|---|---|
Fees per partner | Published averages | £2 million | £0.9 million to £1.73 million |
Fees from clients who follow, in the first year | 21% to 27% of fees per partner | £420,000 to £540,000 | £189,000 to £467,000 |
Fees lost while a replacement comes up to speed | The first-year gap closing evenly over two to three years | £420,000 to £810,000 | £189,000 to £701,000 |
Recruiting a replacement | 20% to 25% of average profit per partner | £67,000 to £84,000 | £67,000 to £84,000 |
Estimated total | Fees lost while a replacement comes up to speed, plus recruiting | About £0.5 million to £0.9 million | About £0.25 million to £0.8 million |
Developing a successor instead | Training, coaching, partners' time and cover | No published figure | No published figure |
The fees per partner come from Moore Kingston Smith's benchmarking of mid-sized UK law firms with revenue of £25 million to £50 million, and from Accountancy Age's ranking of UK accountancy firms placed 11 to 45. The 21% comes from BTI's research and the 27% is the share of clients in the Acritas research who did not stay with the firm. The law firm profit figure is Moore Kingston Smith's average profit per equity partner. The accountancy figure, about £335,000, is the median of pre-tax profit divided by partners for the 16 firms ranked 11 to 50 in the Top 75 Firms Survey 2025 that are set up as partnerships and reported profit. We left out firms set up as companies, because their reported profit is after partners' salaries. Recruiter fees come from US law.
Our own assumption is that the replacement rebuilds the lost fees at an even pace over the two to three years the ALM study found a new partner takes to come up to speed. That makes the fees lost over the period equal to half the first-year gap for each year. The total counts fees, not profit, and it leaves out the costs that are harder to see. A firm that promotes from within avoids the recruiter's fee and pays the costs of developing a successor instead. Your own firm's figures will differ, and the same lines are a useful place to start.
What reduces the risk
Research on client departures finds that relationships held by more than one person at the firm last longer. A study of more than 18,000 client decisions in US lobbying firms, published in Harvard Business Review in 2017, found the chance a client follows a departing professional doubles after they have worked together for three and a half years. That chance falls by about 2.5% for each additional colleague who works directly with the client. A 2016 study of a large US law firm found client billings fell less after a lead partner left where the lawyers serving that client also worked together on other clients. Redwood Analytics studied clients of five large US law firms in 2006. More than half left when no partner worked on their matters, and fewer than 10% left when more than five partners did. Clients receiving a wider range of services were also less likely to leave.
David's advice starts with knowing where the firm depends on one person and treating that as a trigger to plan. He suggests developing the people coming through, so someone is ready to step in. He also recommends having someone with commercial HR experience estimate what a departure would cost, so the firm can plan to reduce it. O'Rielly & Roche adds that "a well-run firm will have a departure contingency plan in place to implement when necessary."
You can read more of David's thinking in why succession planning isn't an HR exercise, or listen to the full conversation on Spotify, Apple Podcasts and YouTube.
See where your firm stands
The Value Readiness Check looks at four areas that shape a firm's value. One of them, leadership, people and culture, covers your pipeline of future leaders, how you retain high performers and build capability, and your succession plans. The Check has 32 questions, takes about six minutes and is free and confidential.
Questions and answers
What is the cost of losing a partner?
No measured figure has been published. Combining published averages gives an estimate of about £0.5 million to £0.9 million for a partner in a UK mid-sized law firm, and about £0.25 million to £0.8 million for a partner in a UK mid-tier accountancy firm. The estimate covers fees lost to clients who follow the partner while a replacement comes up to speed, and the cost of recruiting that replacement. It counts fees rather than profit, and it leaves out costs that are harder to see, such as colleagues who leave later, the effect on the team and lost knowledge.
Do clients follow a partner who leaves?
It depends on the client and the relationship. In the research available, most clients stayed with the firm. In BTI Consulting's research with US corporate counsel, about one in five said they planned to, or were likely to, follow a partner who moved firms. Clients are more likely to follow when the relationship rests on one person and when they have worked with that person for several years. They are less likely to follow when several partners serve them and the firm provides a wider range of work.
How long does a new partner take to perform?
About two to three years, according to an ALM study of lateral partners hired by 100 leading US law firms. Citi Hildebrandt reported in 2015 that only 54% of lateral partners reached break-even five years after joining. We found no comparable figures for accounting firms.
Why are partners leaving Weil Gotshal?
Reporting points to a loss of confidence in the firm's future. Weil's growth trailed its rivals, rival firms offered larger pay packages, partners disagreed on strategy, and the succession of its long-time leader faltered. Reuters reports that more than 30 partners left in 2026, and the Wall Street Journal reports the firm has no debt.
How can a firm reduce the risk of losing clients when a partner leaves?
Spread each client relationship across more than one person. Research in US lobbying firms found the chance a client follows a departing professional falls by about 2.5% for each additional colleague who works directly with that client. Planning succession early, and developing people so someone is ready to step in, also reduces the risk.
