????Fortunes have been made and lost since AOL was last a standalone company. Here are the 10 companies that have lost the most in market value over the past decade.????

????By Colin Barr

????Cisco Systems
????Loss: $425 billion
????Peak market cap: $557 billion (March 2000)
????Recent market cap: $132 billion
????Ticker: CSCO

????Along with Microsoft and Intel, Cisco was one of the big winners of the dot-com boom of the late 1990s. But while the company has remained a top provider of Internet gear, its stock has never recovered from the collapse of the tech bubble. The decline hasn't kept CEO John Chambers (right) from cashing in: He netted $11 million last year via a prearranged stock sale plan.

????General Electric
????Loss: $423 billion
????Peak market cap: $601 billion (August 2000)
????Recent market cap: $178 billion
????Ticker: GE

????GE stock was lofted into the stratosphere by the irrational exuberance of the late 1990s, which meant that there was only one way it could go when CEO Jeff Immelt took over for Jack Welch in 2001 -- down. And down it has gone, shedding 70% of its value and betraying Welch's bluster when he handed over the reins. "It's all going to unfold very nicely," he said then. Not for GE investors it didn't.

????Intel
????Loss: $400 billion
????Peak market cap: $509 billion (August 2000)
????Recent market cap: $109 billion
????Ticker: INTC

????Like Cisco and Microsoft, Intel has long been a successful company -- albeit one that couldn't live up to insanely high expectations. When the stock hit its peak in August 2000, analysts "scrutinized Intel's pronouncements as meticulously as they parsed the syntax of Federal Reserve Chairman Alan Greenspan," as a 2003 UCLA study put it. A month later, Intel trimmed its growth forecasts, sending the stock into a free fall from which it never recovered.

????Microsoft
????Loss: $390 billion

????Peak market cap: $642 billion (September 2000)
????Recent market cap: $252 billion
????Ticker: MSFT

????Microsoft remains the second-biggest U.S. company by market capitalization (after Exxon Mobil), in spite of the sharp decline of its stock. Microsoft has slumped even though it, like Intel, has spent tens of billions of dollars to buy back shares. Microsoft said in the fall of 2008 it had spent $115 billion over five years on stock repurchases and dividends -- a period during which the stock was flat, even with the company's bid.

????Nortel
????Loss: $283 billion

????Peak market cap: $283 billion (July 2000)
????Recent market cap: $0 (bankruptcy January 2009)

????The Ontario-based telecommunications equipment maker was once one of the hottest stocks anywhere. But unlike its former rival Cisco, Nortel shriveled during the bust, amid a swirl of accounting improprieties and bad business decisions. The company pulled the plug in January 2009, filing for bankruptcy and selling off its remaining businesses.