The top five Pittsburgh-area companies, as ranked by revenues, held on to their rankings from last year, and all experienced a jump in sales despite turmoil in the global economy.

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

U.S. Steel remained firmly planted at the top of the list with 2008 revenues of $23.8 billion, up 41 percent from 2007 revenues of $16.9 billion.

Rounding out the top five were PPG Industries, $15.8 billion; H.J. Heinz, $10.1 billion; Nova Chemicals, $7.4 billion; and PNC Financial Services Group, $7.2 billion.

Nova is poised to fall off the list next year pending its agreement to be acquired by International Petroleum Investment Co., an investment arm of the United Arab Emirates government.

Breaking into the top 10 was Mylan Inc., which saw revenues grow by more than 200 percent, from $1.6 billion in 2007 to $5.1 billion in 2008, largely as a result of its acquisition of Merck KGaA's generic drug business.

Several companies fell off the list because they were swallowed up by other businesses last year: Respironics was bought by Dutch firm Royal Philips Electronics; Ansoft Corp. was acquired by Ansys Corp., of Cecil; and IBT Bancorp was bought by S&T Bancorp, of Indiana, Pa.

Other names no longer found on the list are computer and software consultant iGate, which moved its headquarters to Fremont, Calif., and MTR Gaming, the West Virginia-based casino operator eliminated for geographic reasons.

New to the list: Atlas Pipeline Partners, one of the sister companies of fast-growing energy business Atlas America, of Moon; Portec Rail Products, of O'Hara, which provides the rail and freight industries with engineering and products; Moon engineering firm Michael Baker, which fell off last year because it restated financial results; and bank companies Commercial National Financial, of Latrobe, and Allegheny Valley Bancorp, of Lawrenceville.