WASHINGTON - Having become a prominent presence in the nation's capital over the last decade, the Pew Charitable Trusts has formally established a signature residency.

Since December, Pew has been moving much of its widespread Washington operation into a 10-story, refurbished building it bought at 901 E St. NW, across from the headquarters of the Federal Bureau of Investigation.

It is the latest and most concrete step by Pew to secure its position in Washington as a force on national and international issues, ranging from reforming foster care to protecting the world's oceans.

It is also a logical follow to Pew's decision in 2004 to legally change its nonprofit status from that of a foundation to a public charity.

As a public charity with a $3.88 billion endowment, Pew is now able to run programs it once only funded. As a result, it now has about 300 staffers in Washington, up from fewer than 20 in 2003. The new building will put most of those staffers under one roof.

According to Pew president Rebecca Rimel, the new building will have no effect on Pew's Philadelphia initiatives or staffing. Pew's commitment to Philadelphia has been a sensitive issue as its focus on national and international issues has expanded. That sensitivity has increased with the announcement that, following the death of Leonore Annenberg, the Annenberg Foundation was moving from Radnor to Los Angeles.

"The board has been quite clear and consistent," Rimel said, referring to the Pew board of directors. "We love Philadelphia, and we want to support it."

Pew's new building in Washington once housed the Securities and Exchange Commission. It was purchased for $155 million last year. Since then, it has been gutted and refitted and now is a modern, light-filled, glass-and-chrome office space with a primary color scheme that runs from white to gray to black.

Pew plans to occupy about 41/2 floors; the rest of the building will be leased at below-market rates to other nonprofit groups.

So far, Pew has found four tenants: the American Cancer Society, the National Wildlife Federation, the Susan G. Komen Breast Cancer Foundation, and the Alliance for Climate Protection.

The groups share space with about 225 Pew staffers, a number that over time is expected to grow to about 350, according to Rimel.

Not in the building is the Pew Research Center for the People and the Press, an independent, nonpartisan research organization best known for its opinion polls.

"That is by design," Rimel said. "We want to keep that relationship clear. We don't influence them in any way, in what they poll on or the results of that polling."

Even without the 100 staffers that work for the Research Center, Pew's new building will be the home office for more employees than there are now in Philadelphia, the headquarters of the charitable organization founded in 1948 by heirs of the Sun Oil fortune.

Rimel said there were about 180 to 190 Pew staffers in Philadelphia. Those include the trust's top managers, administrative staff, and staff devoted to local programs. In Philadelphia, Pew provides support for local cultural institutions, health and human services organizations, and a variety of "civic initiatives," such as the relocation of the Barnes museum to the Benjamin Franklin Parkway.

Rimel has offices in Philadelphia and Washington. She spends about 40 percent of her time in Washington, she said, where her office is identical in size and design - a full glass front wall, no door - to those of the lowliest staffers.

"I try to be down here at least every other week," she said. "We have a lot of staff down here and a lot of new staff. I believe tone is set at the top, and that is best done with me having face-to-face contact with every new employee."

A number of key Pew managers who now work in Philadelphia but oversee largely Washington staffs will be moving there. Among them is Joshua S. Reichert, managing director of the Pew Environment Group. Other Washington-based units include the Pew Health Group, the Pew Economic Policy Department, and the Pew Center on the States.

The shift in managers and the purchase of the building should not be seen as a lessening of Pew's commitment to the Philadelphia region, Rimel said, but rather a strengthening of national programs that benefit everyone.

"The work we do, whether it is on foster-care reform, or pre-K education, or government performance, is going to benefit Philadelphians and Pennsylvanians in the same way we hope it will benefit people in Austin, Texas, or Charleston, S.C.," she said.

Still, she is mindful that in some local quarters, there remains a suspicion of Pew's ultimate goals and how much the Philadelphia region fits into them.

She counters that Pew has long had a broad vision of its role, which, while including the region, extends far beyond the Philadelphia area.

In Pew's first year of 1948, for instance, 64 percent of the charity's grants were national or international in scope, according to data provided by Pew.

Over the next 30 years, Pew's grants were split evenly between the Philadelphia region and nationally and internationally. Since 1980, about 25 percent of its grants have been local, according to Pew.

While continuing its commitment to Philadelphia, Pew does not intend to play a similar role in the city of Washington, Rimel said.

"While we will be good citizens, we are here because we need to be here, for the talent and the access to accomplish our policy objectives," she said. "And that will benefit Philadelphians and all Americans."

Contact staff writer Christopher K. Hepp at 215-854-2208 or chepp@phillynews.com.