According to Bloomberg, Fortress Investment Group’s bet on subprime lender Springleaf Holdings Inc. (LEAF) has paid off. Fortress invested in Springleaf and Nationstar (NSM) to build out a financial-services business within its private-equity unit. Bloomberg explains:

Fortress, the first publicly traded buyout firm in the U.S., paid $125 million in 2010 for a stake in Springleaf that was valued at $1.68 billion yesterday following the Evansville, Indiana-based lender’s trading debut. Springleaf, which sold 21 million shares at $17 apiece in its initial public offering Oct. 15, gained 13 percent to close at $19.26 in New York.

In addition to Springleaf, Nationstar also proved to be profitable:

The offering deepened New York-based Fortress’s gains from a turnaround in the subprime lending market following the housing collapse. Fortress last year took public Nationstar Mortgage Holdings Inc., a mortgage servicer Fortress had acquired in 2006 for more than $550 million. The stock has more than tripled since then, valuing Fortress’s 75 percent stake at more than $3.4 billion as of yesterday’s close, according to data compiled by Bloomberg.