The new group is a partnership of the American Unity Fund, a super PAC created by the hedge fund executive Paul Singer, as well as the Gill Foundation and the Gill Action Fund. Tim Gill, a Colorado-based Democratic activist and philanthropist, has been a major financial backer of same-sex marriage efforts.

And Mr. Singer and another hedge fund executive, Dan Loeb, were among the financial backers of the efforts in New York, along with then-New York City Mayor Michael R. Bloomberg and Gov. Andrew M. Cuomo, to pass a gay marriage law in 2011.

“We think this needs to be legislated at both a state and federal level, so we’re approaching it from both standpoints,” Mr. Loeb said in a rare interview about his efforts. “There are too many states that don’t have employee non-discrimination acts.”