Private equity firms Fountainvest Capital Partners, TPG and Warburg Pincus are among final-round bidders for Carlyle Group’s stake in AmbioPharm Inc, people with knowledge of the transaction told Reuters.

Carlyle, which is targeting a valuation of $1 billion for Ambio in a sale, is expecting binding bids in the coming days, said three of the people. A deal could be reached by end-September at the earliest, said one of them.

Investment bank Jefferies has been hired by Carlyle to run the sale, Reuters has previously reported. The bank did not immediately comment.

Read more: Reuters