Hedge fund tycoon parting ways with longtime partner James Palotta, whose Raptor Fund lost estimated 7% in 2007, prompting skittish investors to withdraw billions. Tudor Investment's overall assets under management fell 9% to $16 billion in December, now back up to $18 billion. Launched hedge fund 1980. Returned 125% net of fees in 1987 betting that market would crash. Estimated annual returns: 24% net of fees.