Sullivan & Cromwell adds two London M&A partners as Weil resets leadership

On September 17, Reuters reported that Sullivan & Cromwell hired Weil’s London M&A leader David Avery-Gee and partner Sarah Flaherty, with Avery-Gee set to co-lead the firm’s European M&A practice. Their client histories include Advent International, Eli Lilly, Sanofi and Willis Towers Watson, while Weil said it had hired 51 partners since the beginning of 2025 despite a series of senior departures. For BD leaders, the move is a reminder that a lateral’s value depends on relationships, sector adjacency and coordinated global coverage, not the headline size of a team. Client-transition plans should therefore distinguish portable relationships from institutional clients and identify which existing partners must be integrated into the account strategy.