A top aid to Margolies has set up an outside "527" group called Marjorie 2014 and has purchased marjorie2014.com. The former congresswoman is considering a run for the open seat currently held by Rep. Allyson Schwartz (D-Pa.), who is running for governor, and has said she'll decide on a run by the end of May.

Margolies, then Margolies Mezvinsky, was a loyal ally of the Clintons during her one House term, voting for President Clinton's budget and healthcare reform plan despite her old district's toss-up nature and close 1992 election. She lost in the 1994 GOP landslide and hasn't held office since.

Her son, Marc Mezvinsky, married Chelsea Clinton in 2010.

Bloomberg first reported the new outside group.