Mayer Brown saw revenue inch up 0.2% last year to reach a new high of $1.26bn (£1.03bn), while profit per equity partner (PEP) fell 7.1% to $1.45m (£1.19m)

While the revenue mark is a record for Mayer Brown, an overall headcount increase of 5.2% pushed down other financial metrics, including revenue per lawyer, which dropped 4.8% to $795,000 (£653,000).

Meanwhile, the PEP drop – which came as the firm's equity partnership grew by 3.1% – marked a return to 2014′s level, following a 7.6% surge in 2015 to a high of $1.56m (£1.28m).

Highlights for Mayer Brown in 2016 included opening an office in Dubai; raiding K&L Gates to bring on more than 30 consumer finance lawyers in Washington DC; and scoring a US Supreme Court victory for client Spokeo in a landmark case that rolled back standing guidelines for plaintiffs in class actions.

"[In 2016 the firm had] its best year ever in terms of revenue and demand from our clients, and the second-best year in our history with regard to net income and profits per partner," said Chicago-based chairman Paul Theiss, who has led Mayer Brown since 2012. "And it continues, we think, a very strong run of four years."

Partner profits under Theiss's leadership have risen by 26%, while revenue has increased by 15%. Mayer Brown is one of the largest US firms by headcount – it ranked 15th on The National Law Journal's NLJ500 last year – but the firm's lawyers are less spread out than some of its global peers.

The firm has offices of more than 200 lawyers in five cities: Chicago, Hong Kong, London, New York and Washington DC. Mayer Brown said it is the only firm with more than 200 lawyers in the world's three largest financial centres of Hong Kong, London and New York.

The firm declined to provide revenue or PEP for its London office. London senior partner Sean Connolly said: "As an office, last year we saw a relative cooling of transactional activity. This was caused by uncertainty surrounding the EU referendum, which slowed domestic transactions and inwards international investment.

"Nevertheless, we saw a welcome return to high levels of activity in Q4 as the marketplace responded to the referendum result and the softening of sterling produced investment opportunities for overseas clients. This uptick in Q4 has carried through to the first two months of 2017 and we expect to finish Q1 ahead of budget."

Last year, more than 50% of the firm's 100 largest clients by hours billed utilised the firm in all three of its regions: Europe, Asia and the Americas. A full 80% of those clients used the firm in at least two of those regions, Theiss said.

"Those numbers have gone up dramatically over the last four years, and it's a signal of our clients continuing to turn to Mayer Brown for their most complex matters," said Theiss.

Mayer Brown made 49 lateral partner hires last year and made up a further 27 lawyers to partner. The laterals included Daniel Stein, a former chief of the criminal division in the US attorney's office for the Southern District of New York; and Marjorie Loeb, a former senior vice-president and general counsel at Fiat Chrysler Automobiles. Mayer Brown's Brazilian arm, Tauil & Chequer, also added Luis Adams, former attorney general of Brazil.

The firm's largest deals last year included representing Wells Fargo on its $32bn (£26bn) acquisition of the commercial distribution finance and vendor finance business of GE Capital, as well as TransCanada on its $13bn (£10.7bn) acquisition of Houston-based Columbia Pipeline Group.

Mayer Brown's immigration practice also got a shot in the arm recently when President Donald Trump issued an executive order barring immigration from seven predominantly Muslim states. The firm wrote an amicus brief for a case before the US Court of Appeals for the Ninth Circuit, which resulted in a suspension of the controversial ban. Theiss and other lawyers have said that immigration has become a hot topic for their global clients.

"Three years ago, I wouldn't have said that was a particularly acute need for our clients," Theiss said.