Revenue in Sidley Austin‘s London office climbed by almost a third year-on-year in 2025, rising by 32% to hit $299m.
The increase, which came against a 9% hike in global revenue to $3.74bn, means the firm’s London office alone generated enough fee income to sit within the UK top 40 last year. London turnover for 2024 stood at $226.7m.
London managing partner Tom Thesing told LB that the scale of the turnover increase was rooted in a ‘broad based contribution from different practice areas and a diversified business model.’
‘There was a high level of activity across the board,’ he continued, noting transactional, regulatory, disputes and restructuring as key areas. ‘This base reflects the investment the firm has made into the London office.’
The firm serves more than 80% of its top 50 clients from its London office, with more than 90% of its top 50 London clients using two or more London practices in 2025. ‘It’s crucial that we can serve clients, regardless of whether they end up listing in New York, London or in Europe,’ said Thesing.
Since kick-starting a wave of City investment in January 2023, the Chicago-founded firm has added 26 lateral partners, and has made up 10 partners internally. The majority of the laterals have been in capital markets, private funds, and leveraged finance, where the firm hired a five-partner team from Latham & Watkins in 2024.
It has continued to add more partners from Latham, hiring high yield partners Scott Colwell and Patrick Kwak in October that year and finance partner Tania Bedi in December. Last April, Sidley brought London corporate co-chair David Stewart into the firm, also from Latham.
Globally, profit per equity partner (PEP) jumped 15.4% from $4.6 to $6m in 2025 – a significantly larger increase than last year’s 10.3% increase.
Confirmation of the growth comes as Sidley prepares to introduce a new salaried partner tier in 1 June. Commenting on the new tier Thesing said: ‘We felt it was important to show the market we can develop and that we have a progression path that’s consistent with other firms in the market.’
Thesing said hiring would continue as the firm looks to bolster areas where there is rising client demand. ‘We’ve seen clients turn to us for matters surrounding international trade and sanctions in greater volumes that in the past,’ he said, noting ongoing geopolitical volatility.
Sidley has continued to make major hires in London into 2026, with restructuring duo Philip Hertz and Melissa Coakley joining from Clifford Chance last month. In addition, the firm added Latham’s former global real estate co-chair Jeremy Trinder in January and UK capital markets co-head James Inness last month.
The firm has also stayed active on its US home turf, bringing Cravath capital markets partner Scott Bennett into its New York office earlier this month.
‘The lateral market remains somewhat disrupted so we believe there will be more moves,’ Thesing said. ‘Where our clients are looking to grow their businesses, we will look to grow alongside them.’
The firm’s global partner promotions round, announced in December, saw three lawyers added to the partnership in London, in private equity, litigation and global finance. The firm promoted 29 partners globally, down from 38 in 2024.
