More from these and other firms are expected to follow.
The latest recruits to join from Clifford Chance are senior banking litigator Michelle Duncan and three banking assistants, Kate Hallchurch, Emma Webster and Antonia Rawlinson.
Banking and capital markets lawyers Erica Handling and Doug Urquart from Allen & Overy's New York office have also joined. Handling moves to London and Urquart will stay in New York. Both act for US investment banker Bear Stearns, one of a number of US clients Weils Gotshal want to woo in London.
Linklaters associate Lawrence Cole-Morgan has also moved.
The new arrivals join London office head Maurice Allen, the ex-Clifford Chance banking expert, and other partners: former Clifford Chance partner Martin Hughes, former Linklaters capital markets partner Nia Morris, former Merrill Lynch director Nick Holt and senior assistants Sean Pierce and James Chesterman from Linklaters and Freshfields respectively.
Two US partners - David Lefkowitz and Doug Warner - are also expected to move to Weil Gotshal soon.
Allen said: "We are at an advanced stage of recruiting another half-dozen, virtually all from the main banking and capital markets firms.
"A lot of good people in London are clearly not happy with the lack of partnership prospects or rewards in some big firms."
Allen's City team is based temporarily at London Wall, within sight of Clifford Chance's offices.