How easy it is to forget that the University of Pittsburgh Medical Center is a nonprofit.

The region's largest employer yesterday said it actually earned $459 million through the first nine months of fiscal 2007 on record revenues of $5 billion, and it is on pace to exceed its eye-popping performance of 2006, when its "excess margin" -- earnings in excess of operating costs -- soared 77 percent to $512 million and revenue nearly exceeded $6 billion.

The results, which include $279 million in gains from UPMC's investment portfolio, are just the latest example of for-profit behavior from an Oakland health care conglomerate that employs 43,000 in Western Pennsylvania, already controls 19 hospitals and accounts for more than 48 percent of all patient discharges in Allegheny County.

And it wants more: A proposed merger with Mercy Hospital would push its share of the market higher than 50 percent, prompting criticism from UPMC rival West Penn Allegheny Health System that such a union would nudge health care prices higher and give consumers less choice. Both the Federal Trade Commission and the state attorney general are reviewing the potential hookup.

"We believe strongly that patients, employers, insurers, civic leaders and health care professionals should be concerned about the negative ramifications to this region if UPMC is successful in acquiring control of the market and thereby lessening choice in health care," said Tom Chakurda, a West Penn Allegheny spokesman.

UPMC has been aggressive on other fronts, as well:

Marketing. It paid $1.1 million last year to wrap its name around Port Authority buses and an undisclosed amount to advertise its cardiac care, cancer and gynecology services across a 3,000-foot-high screen in New York's Times Square, with a 30-second UPMC spot running every half-hour between Christmas and New Year's. The purchases were part of $14.2 million spent on advertising last year, according to Nielsen Monitor Plus.

Air travel. It upgraded flying options this year by leasing a Bombardier Global Express jet to serve international locations in Ireland, England, Italy and Qatar. UPMC would not disclose the leasing costs. It did note that the new jet, which can fly between any two points in the world with only one stop, would replace another one leased in 2005 (at a cost of $1 million a year, according to a former UPMC spokeswoman). That is unless "increasing international demand requires two," said current UPMC spokesman Frank Raczkiewicz, citing potential health care activities in "other European and Mideastern countries."

Office space. It signed a lease for 500,000 square feet inside Pittsburgh's largest and most expensive office building, the U.S. Steel Tower. The deal is valued at $250 million over 20 years, according to real estate Web site GlobeSt.com (UPMC and the building's leasing agent would not confirm that figure). UPMC, which will place its executive offices and boardroom on the top leasable floor, also signaled its desire to place the UPMC logo on all three sides of a structure built for an icon of Pittsburgh's industrial age. Such a move has to be approved by the city planning commission.

The spot atop Pittsburgh's largest building, the new jet and the Times Square advertisement are all "consistent with the way UPMC conducts itself," said Cliff Shannon, president of Churchill-based Small Business Councils, a small-business lobby. "They are not shy. They are not bashful. They do not retreat."

But is that aggression a good thing -- especially when UPMC's nonprofit status allows it to avoid some financial requirements that apply to for-profit enterprises?

"It is very tough to be unequivocal about them," said Mr. Shannon. "They do wonderful things. They are a bulwark of the regional economy at a time when most of the region's economic and civic power has been pulling back and playing defense. ... It is really difficult to overestimate the importance of UPMC to the regional economy.

"That said, how can an outfit that made $500 million last year hide behind state laws that exempt it from property tax? It just seems completely out of proportion that arguably the most profitable enterprise in the region is exempt from all these taxes."

UPMC, Mr. Shannon said, pressures vendors and professional-service firms to do business only with UPMC and not its rivals, using its size as leverage, just as a for-profit would. But "they are not trying to portray themselves differently than they are. They aim to win."

And there is little doubt that UPMC continues to reinvest its earnings in people and projects.

Through the first nine months of fiscal 2007 that ended March 31 -- as revenues increased 13 percent and profits, or "excess margin," rose 17.6 percent -- UPMC added 170 physicians to its staff for a total of 2,300. It also invested $348 million in new construction, including $136 million on the building of a new Children's Hospital in Lawrenceville.

If it receives approval to merge with Mercy, UPMC pledges to retain the 3,000 jobs, reinvest in the Lower Hill District, and donate $30 million to the Pittsburgh Mercy Foundation in equal amounts over a six-year period to support its mission. It also said it will maintain Mercy's history of providing a high level of uncompensated care to the community -- about $25 million in its latest fiscal year (UPMC provided more than $200 million).

UPMC dismisses concerns that the takeover would result in higher prices or less competition. But if the deal falls apart, UPMC President Jeffrey Romoff argued at a press conference last month, patients will migrate to UPMC anyway and the Hill will lose its chance for new investment.

"We are confident the attorney general will see this issue as we have," he said.