Key points:

• Simpson Thacher & Bartlett is advising Perkins Coie and Davis Polk & Wardwell is advising Ashurst on a proposed transatlantic merger.
• The planned Ashurst Perkins Coie firm would have about 3,000 lawyers, 52 offices in 23 countries and roughly $2.7 billion in combined revenue.
• Both New York firms are reprising roles they held on the Allen & Overy–Shearman & Sterling tie-up, cementing a niche as counsel to major law firm combinations.

Davis Polk & Wardwell is advising Ashurst and Simpson Thacher & Bartlett is counselling Perkins Coie on their planned merger, a deal that would create Ashurst Perkins Coie, a top-20 global firm by revenue. The firms announced their intent to combine on Nov. 17, outlining a “combination of equals” that would unite more than 3,000 lawyers across 52 offices in 23 countries, with projected annual revenue of about $2.7 billion, according to the joint statements from Ashurst and Perkins Coie and subsequent coverage by Reuters. 

On the Simpson Thacher side, the deal team for Perkins Coie is led by New York M&A partners Eric Swedenburg and Anthony Vernace, according to people familiar with the talks. At Davis Polk, Ashurst has turned to a corporate team that includes partner William Aaronson and the firm’s chair and managing partner, Neil Barr, with tax partner Michael Mollerus advising on structuring. All are based in New York, underscoring Wall Street’s central role in transatlantic law firm consolidation, even when neither of the legacy firms is headquartered there.

The Ashurst–Perkins Coie proposal comes amid an active cycle for large law firm combinations. Ashurst and Perkins Coie have framed their deal as a way to build a more integrated platform in technology, financial services, energy and infrastructure, with flagship hubs in Seattle, London, Sydney and New York, as set out in their combination announcement and related releases carried by Perkins Coie and Ashurst. 

Firm leaders have said they will conduct partner roadshows over the coming months, with votes expected in early 2026 and a target to complete the merger by mid-to-late 2026, subject to approvals and regulatory conditions. External analysis from legal data provider Pirical suggests the combined outfit would significantly expand Ashurst’s U.S. footprint while adding international depth for Perkins Coie, particularly in Europe and Asia, placing Ashurst Perkins Coie firmly in the Global 200’s top-20 range by revenue and headcount as mapped by Pirical. 

For Simpson Thacher and Davis Polk, the mandate extends a pattern. Both firms previously advised on the Allen & Overy–Shearman & Sterling merger: Davis Polk acted for Shearman, while Simpson Thacher represented Allen & Overy, according to the firms’ own deal announcements and subsequent reporting from outlets including Bloomberg Law and the Global Legal Post from Davis Polk’s experience summary and Bloomberg Law’s Wake Up Call. 

Davis Polk is also currently advising Cadwalader, Wickersham & Taft on potential merger options, including confidential discussions with Alston & Bird, according to recent reports from Bloomberg Law and other legal industry outlets describing Cadwalader’s engagement of Davis Polk. 

The Ashurst Perkins Coie deal continues a broader trend of transatlantic tie-ups, following combinations such as A&O Shearman and the recently announced merger between Herbert Smith Freehills and Kramer Levin. Commentators have noted that, while financial metrics and geographic fit drive much of the current activity, integration challenges - particularly around partner compensation, governance and conflicts - remain significant.