Wall Street's worst year since 1931 vaporized billions in shareholder wealth, devastation that is apparent in what happened to the cumulative value of the Post-Gazette's Top 50.

		Top 50 rankings • See the rankings for this year's Top 50 in Business report.

PNC Financial Services Group repeated as the region's largest company based on market capitalization -- the number of its publicly traded shares multiplied by the price of a single share -- even though its current market cap of $10.3 billion is less than half of the $21.7 billion cumulative value the market placed on its shares last year.

The same market cap would have landed PNC in the No. 6 slot last year.

The shrinkage reflects deep-seated concerns about financial institutions, worries about PNC's year-end acquisition of troubled National City Corp., and the bank's decision to slash its dividend by 85 percent.

H.J. Heinz retained the No. 2 spot, with a market cap of $10 billion, down from $14.3 billion last year.

The list is based on the market cap of Top 50 public companies as measured earlier this month. At that time, the cumulative value of all of the stock of 50 public companies based in the region was about $69 billion, down from $151 billion a year ago.

The drop reflects last year's 38 percent drop in the S&P 500 and the fact that shares of 45 members of the Top 50 fell in 2008. The drop also reflects the 20 percent stock market decline in the first two months of this year and a change in the composition of the Top 50.

Gone are Respironics, a $5 billion market cap company acquired by Royal Philips Electronics, and four other companies that had a combined market cap of $1.3 billion -- Ansoft, iGate, MTR Gaming and IBT Bancorp.

The five companies that replaced them -- Michael Baker, Atlas Pipeline Partners, Portec Rail Products, Commercial National Financial and Allegheny Valley Bancorp -- had a combined market cap of only $594 million.

Last year, half of the Top 50 had market caps greater than $1 billion. This year, only 16 topped that mark.

Despite volatile markets, the Top 10 didn't change all that much. There were two new entrants: Cecil generic drug maker Mylan, ranked 14th last year, and American Eagle Outfitters, which moved up from the No. 11 spot. They replaced Allegheny Technologies, which slid to 11th place after its shares tumbled 71 percent last year, and Respironics.

The smallest company on the list is Wizzard Software. The speech recognition software company has a market cap of about $26 million, making it less than 1 percent the size of PNC.

Last year's smallest Top 50 member, WVS Financial, moved up to the 46th spot this year.