Thomas H. Lee Partners and Warburg Pincus are selling the rest of their stock in Umpqua Holdings in Portland, Ore.

The $22.5 billion-asset Umpqua filed documents Tuesday for the secondary offering, disclosing that the private equity firms will collectively sell roughly 28.3 million shares of stock, or a 13 percent stake in the company. Another 2.9 million shares, borrowed by an affiliate of Barclays, will be sold to hedge exposure to certain warrants.

Umpqua will not receive any proceeds from the sales.

The private equity firms gained their stakes after Umpqua bought Sterling Financial in Spokane, Washington, for roughly $2 billion earlier this year. The firms, which also sold shares of Umpqua stock a few months ago, led a $730 million recapitalization of Sterling in 2010.