At a time when New York City hospitals are leaning heavily on philanthropic dollars to stay afloat, New York Downtown Hospital is courting the financial community it serves.

Situated on William Street, it is the only hospital in Lower Manhattan, and as such, it is a health care provider not only for nearby inhabitants, but also for the money managers, financiers, and city lawmakers who work — and, sometimes, fall ill — downtown.

Hospital officials estimate that of the 33,000 emergency room patients it treats each year, one in four comes from the downtown work force; 2,500 of them are cardiac cases.

“We’re the nearest hospital to the financial district,” the administrative director of the hospital’s Emergency Department/Emergency Medical Service, Peter Fromm, said. “We’re the closest, we’re the best, we’re the quickest.”

Recent gifts from the corporate community signal recognition of a mutually dependent relationship. In September, the hospital opened its $25 million Lehman Brothers Emergency Center, built with $5 million from Lehman Brothers, plus $1 million each from the New York Stock Exchange, the Starr Foundation, the Bank of New York, and JPMorgan Chase. American International Group Inc. bought the emergency center a $1.4 million, 64-slice CT scanner.

Other corporations have made smaller gifts, such as Citigroup’s $400,000 for a decontamination suite, and Moody’s Investment Service’s $200,000 to the obstetrics and gynecology department and another $150,000 for a new ambulance.

Founded in 1857 by Elizabeth Blackwell, the hospital traces its corporate roots to 1922, when Wall Street financiers became involved with the hospital after a bomb was set off outside J.P. Morgan & Co. in 1920.

Because it is so close to the city’s financial district, courthouses, and City Hall, the hospital has played a historic role in responding to high-profile emergencies. It treated victims of the 1993 and 2001 World Trade Center attacks, and in 2001, medical staff saw some 600 patients within three hours of the attacks. In 2003, when a gunman shot and killed City Council Member James Davis inside City Hall, Davis and the gunman both were rushed to the downtown hospital.

Because of its share of patients who work nearby, New York Down town officials said the busiest shift is between noon and midnight during the week, rather than on the weekend.

“It’s a fascinating situation be cause this is a hospital that is doing everything it can to simultaneously serve those permanently living downtown and, at the same time they’re trying to serve this transient community on Wall Street,” a man aging director at Goldman Sachs and a hospital trustee, Peter Gross said. Although some business exec utives may head off to Westchester or Connecticut for primary care, he said, the Downtown Hospital works hard to accommodate the urgent needs that arise.

“What you end up having is, when somebody has a heart attack, all of a sudden, their greatest friend in the world is New York Downtown Hospital,” Mr. Gross said.

Part of catering to corporate patients includes a “Downtown HeartSavers” outreach program that promotes cardiac health, as well as a special hotline for companies to call the hospital in case of emergency.

Philanthropy plays a “huge” role in sustaining the hospital, Mr. Gross said. “The hospital really does rely on the giving of institutions.”

The head nurse at an in-house clinic at the New York Stock Exchange, Rosalyn Hochberg, likened her interactions with the hospital to a well-oiled machine.

“I’ll call Peter [Fromm] and the ER directly so they’ll know what we’re sending over,” she said.

At the hospital’s new emergency center, the role the hospital played on September 11, 2001, is apparent.

In the ambulance bay, the center has a $1 million decontamination system with 19 showerheads that can decontaminate up to 1,000 people an hour, if necessary.

Inside, there are 32 patient rooms, each 120 square feet in size, that can accommodate one or two patients. Opposite is a nursing station designated for cardiac care nurses, where a plaque with “Cipriani” adorns the wall.