[8][9] After a dispute with Lazard's chief executive Bruce Wasserstein over compensation,[10][11] he left in 2003 to start his own hedge fund, Cantillon Capital Management.
[12] As a result of his departure, Lazard's hedge fund business suffered a devastating loss of $3 billion, as many of its investors followed von Mueffling to the new firm.
[13] In 2007, he was named one of New York magazine's "hedge-fund elite" along with the likes of Chase Coleman, Peter Thiel and Eric Mindich.
[20][21] He also helped launch whosontheballot.org, a website that provides one-stop comprehensive guide for all things related to voting in New York City.
[12] In 2007, he served on The President's Working Group on Financial Markets, where he was named to the Asset Manager's committee and helped draw up guidelines for best practices in the hedge fund industry.