A guide to law firm mergers

The reasons that firms decide to merge are as varied as the firms themselves, but there are usually some key drivers – namely, the desire to expand, geographically or in terms of expertise, or to stay afloat. For the lawyers who find that the firm they joined is no longer the firm at which they work, there are normally a raft of opportunities and maybe especially so for trainees.

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Mergers can be an extremely effective way for law firms to expand and reduce costs. Therefore, you’re never too far away from a story about a law firm merger – either contemplated, being negotiated or completed.

2025/26 – a strong year for mergers?

In the first half of 2025, global M&A increased by 30% to a value of $1.9 trillion, representing the strongest year to date since 2022, according to the London Stock Exchange Group (LSEG). Private equity backed M&A boomed, with the first half of 2025 ranking as the third largest opening period for private equity M&A since records began in 1980.

The LSEG notes that, while global uncertainty creates an environment for mega deals, mid-market companies, which are typically more aligned with M&A growth, are more likely to hold off in times of instability. Reflecting this, deals of less than $500 million fell by 2% in the first half of 2025.

Heading into 2026, merger activity is “entering a new phase”, according to PwC, with overall deal values increasingly driven by large, strategic transactions and AI‑led investment. The surge in mergers across the wider market was also mirrored in the legal sector, with an upward trend in 2025. Fairfax Associates tracked 59 mergers in 2025, an 18% increase from 2024. Looking forward, 16 mergers have already been announced for 2026, including Hogan Lovells and Cadwalader, Wickersham & Taft, Ashurst LLP and Perkins Coie, and Winston & Strawn LLP and Taylor Wessing to name a few. As merger activity increases, it’s important for aspiring lawyers to consider the reasons behind the mergers.

What are some of the factors that lead firms to merge?

There’s usually not one single reason that causes law firms to merge – rather, it’ll be a unique set of conditions and aims that combine to draw them together. Nebulous? Perhaps! But there are some common drivers that tend to sit behind merger discussions.

Growth is a key consideration in many cases. Kent Zimmermann, principal at Zeughauser Group, which advises law firms on strategy and mergers, told Bloomberg Law: “More and more firms are appreciating the benefits of scale and recognizing that it’s hard to build enough scale with one-offs, laterals and an occasional group hire.”

This growth can be geographic or practice-area focused. When growth is geographic, it’s often pursued cautiously. Founder and CEO of legal recruitment consultancy Millbourn Ross David Sparkes explains: “Firms tend to grow out in well-managed concentric circles. They look for somewhere that overlaps with their existing client base but provides enough opportunity to find more clients in another area.”

Technological change is also playing an increasingly important role. Co-chair of the International Bar Association law firm management committee Paul Marmor says: “What’s driving people forwards are the technological developments, where at the higher end of the market people are grappling with the onset of [AI], new tech [and] new developments and are simply coming together to pool resources or are starting to think about it.” 

Other commercial and structural pressures can also prompt firms to consider merging:

• Client driven forces – a law firm is responding to requests from its clients to provide services in locations or practice areas that it doesn’t already cover.
• Financial pressures – a law firm needs to join forces with another to mitigate against a precarious financial position.
• Improved market position – a law firm wants to solidify its position and will strengthen its position by joining with another.

Some or all of the above factors have driven more law firms to merge this year. But as mergers become more common, it raises the question: what makes a union successful?

Turning a merger into a functioning firm

Once a merger is agreed, attention quickly turns from strategy to execution. Practical details and logistics are key to success. This includes, but isn’t limited to, office location, IT integration, salary integration and redundancies.

The relative size of the firms involved can also influence how a merger plays out in practice. Paul Bennett, a partner at legal consultancy Bennett Briegal, commented that where combinations are uneven, power dynamics can quickly emerge. Bennett explained that “if it’s a 75–25 merger, the bigger firm will dominate”, but also added that the key question is what each firm delivers in terms of “productivity and client excellence”.

Alongside these structural considerations, law firms must ensure that they’re on the same page in terms of their respective approach to:

• non-billable time;
• diversity and inclusion;
• pro bono work; and
• the importance of communication between the partnership and other staff.

Additionally, different considerations can arise where firms are exploring alternatives to a traditional merger. If a private equity model is being considered, questions around ownership and control come more sharply into focus. Marmor notes: “There’s a trade‑off because it depends how much of the equity the house is taking and whether the partners retain control.”

So, when a merger is proposed, law firms must be aligned, both ideologically and practically.

Check out this Feature to find out more about M&A, private equity and litigation funding.

What about when talks fail?

Merger failure isn’t unusual. Before Shearman & Sterling merged with Allen & Overy LLP, it had had failed talks with Hogan Lovells in 2024. After the pair abandoned talks, the firms released a statement explaining that they’d “mutually agreed that a combination at this time isn’t in the best interest of either firm”.

It’s often the case that failure to merge can sometimes simply be the result of the pre-merger investigation and due diligence, and a realisation that the firms aren’t actually a good match – you could call it the very definition of an ‘amicable split’.

Other reasons might lead to relations becoming more acrimonious, including an inability to agree on key elements of the deal. Leadership can also be a point of contention. We can only imagine that there’s sometimes a non-negotiable problem of senior figures vying for position, or even so serious a personality clash that the deal can’t survive.

Even where talks progress, some level of fallout is often expected. Commenting on the proposed Ashurst LLP and Perkins Coie merger, a partner at Lexington Consultants, Moray McLaren, says: “Some Perkins Coie partners will leave – that’s not unusual in a merger of this scale. You simply can’t please all of the people, all of the time. The real question isn’t whether there’s attrition, but whether the firm retains the people and client relationships that matter most to the future strategy."

For firms that manage this transition effectively, the focus can then shift outward to the potential benefits of a merger.

What are the specific benefits for clients?

Provided the merger has been implemented carefully, there are clear benefits for clients – in fact, the merger will often be driven by the needs of those very same clients who want their lawyers to be able to advise on the legal rights and obligations in other jurisdictions or cross-sector.

While law firm mergers look to benefit all parties involved, including clients, the gain isn’t always recognised. Factors that firms must take into account when in merger talks include culture, pricing, profitability and systems, as laid out in a Lexology article by CM Murray LLP. By failing to spend time on all elements, mergers can have a backwards impact on clients. If systems aren’t integrated effectively, for example, clients may feel dissatisfied and eventually look elsewhere for their legal services needs to be met.

In 2024, the Solicitors Regulation Authority (SRA) released a warning notice, emphasising the importance of prioritising clients’ interests when carrying out mergers. The statement highlights the dangers of making multiple acquisitions in a relatively short period of time.

For example, the Metamorph Group acquired several high-street law firms in quick succession before being shut down by the SRA and some clients of the merged firms reported financial losses.

The feeling seems to be that provided the proposed changes and the new reality are communicated effectively to the client, much of the sense of upheaval and disruption can be minimised. As with so much in life, communication is key!

What are the benefits for trainees?

There are many advantages for trainees; both those already at the merging firms and those who’ve been recruited but are yet to join. Mergers can bring rapid changes to a trainee’s working life.

Kush Patel, a trainee who joined Shearman & Sterling before its merger with Allen & Overy, describes how quickly the change was felt on the ground: “The merger completed in May, and by June, I was working in a completely new office.”

Being part of a combined outfit can bring a whole host of benefits. Some of those advantages include access to:

• more opportunities to travel or be seconded to new offices;
• different types of work and new clients;
• enhanced learning and development opportunities; and
• different seat options.

For example, Patel explains: “Allen & Overy had this homegrown AI system called Harvey […] We didn’t have that at Shearman. This has been a really exciting thing to come out of the merger because it’s made my life a lot easier and I’ve had a taste of innovation and technological advancements I hadn’t seen pre-merger.” 

One thing that might worry potential trainees is what happens when a law firm announces it’s due to merge after you’ve been offered a training contract, but before you start at the firm. Evidence suggests that most law firms will try to honour pre-existing offers, but you may find yourself joining a firm that’s different in shape and size from the one that you signed up for.

For example, before the merger, Allen & Overy used to offer 80 training contracts, compared to Shearman and Sterling’s 12. Combining these intakes led to a larger‑than‑typical qualifying cohort immediately after the merger. In July 2024, this resulted in a lower‑than‑average retention rate of 66%, with 37 of 56 trainees retained. This outcome was widely expected given the inflated cohort size caused by the merger, as reported by Legal Cheek. The 66% figure sat below Allen & Overy’s final pre‑merger retention rate of 77% and Shearman & Sterling’s historic 80%‑plus retention levels.

More recent retention rounds show variation across successive post‑merger trainee cohorts. In February 2025, trainee retention at A&O Shearman rebounded to 84% of a cohort of 37 trainees, before dipping again in July 2025 to 69% of a larger cohort of 54 trainees. By January 2026, retention had increased again, with 32 of the 42 spring 2026 qualifiers retained, equating to a 76% retention rate.

Meanwhile, law firms will be thinking about how to manage the transition in as smooth a way as possible, but there’s likely to be an understandable feeling of upheaval and disjointedness. As ever, though, the way you handle the unexpected is up to you – roll with the new set of circumstances and focus on the potential benefits, and you’re likely to feel better about the new proposition. If you resist the reality and put up obstacles, things are likely to go less well.

Examples of recent mergers

A number of major mergers completed in 2025, with an upwards trend in cross-border activity, according to Fairfax Associates. The two largest deals saw Atlanta-based Troutman Pepper combine with Dallas-based Locke Lord, creating a firm with 1,630 lawyers, while two New York firms merged to create McDermott Will & Schulte UK LLP, which has a combined practice of 1,699 lawyers. Other 2025 mergers included Herbert Smith Freehills’ consolidation with Kramer Levin. Operating under a single profit pool, the merged firm generates global revenues of approximately $2 billion and gives Herbert Smith Freehills access to a significantly expanded US platform through Kramer Levin’s offices in New York, Washington, DC, and Silicon Valley.

Alongside completed deals, a wave of merger announcements throughout 2025 set the tone for 2026. In November, a tie-up was announced between US law firm Perkins Coie and British silver circle firm Ashurst LLP, with both having recently posted strong financial results and invested heavily in expanding their AI capabilities. The trend of US and UK combinations continued with the planned consolidation of Taylor Wessing’s UK arm and Winston & Strawn LLP, which is expected to generate revenues of around £1.2 billion. Upon approval in February 2026, Taylor Wessing UK managing partner Shane Gleghorn stated: “Our clients require a firm with premier teams in those hubs in relation to critical transactions, litigation, IP and private wealth. Our partners, therefore, voted in favour of the combination because both firms have an absolute commitment to achieving our clients’ objectives, and that focus will be the foundation of our shared success.”

Another major union announced in late 2025 was Hogan Lovells’ proposed merger with New York‑based Cadwalader, Wickersham & Taft, described by the firms as the largest law firm combination in history. The deal would create Hogan Lovells Cadwalader, a transatlantic firm with more than 3,100 lawyers and annual revenues exceeding £2.7 billion, ranking it among the world’s five largest law firms by revenue. The move builds on Hogan Lovells’ own origins as the product of a 2010 merger between Washington, DC, based Hogan & Hartson and London‑based Lovells, reinforcing the firm’s experience of integrating US and UK practices.

Commenting on the proposed deal, managing director in the partner practice group at Major Lindsey & Africa, Filippo Falchi, commented: “The fact that one party to this deal has already been through a similar merger before [...] bodes well for its outcome. From a talent standpoint, blending two different firm cultures can be somewhat of a challenge, particularly when a firm has a very distinct ethos. Having an established track record of successfully merging US and UK firms is a positive sign in that regard.”

So, as you can see from the above examples, the reasons that law firms merge vary. However, for the merger to be a success all parties involved must be on the same page. If a law firm you’re applying to has recently merged or is in talks to, it’s vital that you spend some time researching the plans and the reasons behind the talks. Make sure you understand the relationship between the law firms involved and how the merger will impact the newly formed firm’s clients, employees, reach and/or expertise.

Ellie Nicholl (she/her) is a senior content and engagement coordinator at LawCareers.Net.