Fortune 500 rank: 30
2007 loss: $7.77 billion
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. NEXT: Advanced Micro Devices