Atlanta-headquartered King & Spalding's New York office has suffered four high-profile defections in the last five weeks, with one defector labelling the office "a dead duck" that is overly dependent on Georgia-generated work.
Co-head of M&A John Graham left for Clifford Chance; finance partner Dominick DeChiara and senior associate Brad Vaiana quit for Nixon Peabody; and last week private funds head Stephen Culhane joined Linklaters.
Although the departures were separate, a deserter described them as a snowball effect.
Despite two team heads leaving, King & Spalding said it was a "mischaracterisation" to suggest it was suffering depletion.
Michael O'Brien, New York managing partner, went as far as denying that Graham was head of M&A, claiming he was just "a key participant" in the M&A group and that Graham's "large number of clients had not followed him".
Overall, King & Spalding's turnover grew by nearly 10 per cent last year, with average profit per equity partner (PEP) at £611,000.
Departing partners agree that the 785-lawyer firm is generally doing well under new chairman Robert Hays but that there has been a lack of investment in the New York office for more than a year.
A former partner said: "It's been all talk and no action. With 50 or so other firms in the market, it was increasingly hard for us to get business."
Between 2001 and 2004, the New York office of King & Spanding doubled in size to 180 lawyers.
That growth has slowed and two years on the firm has just 185 lawyers.