12. Sanmina-SCI
Fortune 500 rank: 405
2009 revenue: $5.2 billion
2009 total shareholder return: 291.1%
The company's ongoing restructuring finally appears to be bearing fruit, as the electronics maker for brand-name companies recently smashed analysts' profit expectations.
But the company remains dependent on a small pool of customers, many of whom are consolidating to fewer manufacturers. The loss of a major buyer could send the stock into a tailspin.
NEXT: 13. Western Digital
