The Fortune 500's biggest losers

Merrill Lynch was Wall Street's most aggressive player in the once-soaring housing market. But when real estate went sour last year, it ended up costing CEO Stan O'Neal his job. Merrill took an $8.9 billion write-down last October when it realized that its huge portfolio of subprime mortgage-backed securities wasn't worth what it thought it was.

Merrill's losses were not out of line with other big banks'. But Merrill's comparatively smaller investment banking and wealth-management businesses (which both saw record revenue and profits last year) couldn't make up the shortfall.

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