Written by Maureen Farrell and Rob Copeland As workers around the country frantically negotiate severance packages amid tens of thousands of layoffs, employees in a tiny, influential and often secretive corner of Wall Street are being promised some of their biggest paydays ever. Welcome to the world of elite hedge funds, where risky bets using esoteric number-crunching and cutthroat strategies, applied to the same economic and market uncertainties that have roiled corporate America and led to job cuts, have produced gigantic profits. Last year, Citadel, a hedge fund run by Kenneth C. Griffin, made $16 billion — the largest annual...