A private equity consortium comprising Warburg Pincus and Advent International is in advanced talks to acquire medical device maker Baxter International Inc’s (BAX.N) biopharma solutions business in a deal that could reach or exceed $4 billion, people familiar with the matter said on Sunday.

Warburg Pincus and Advent have submitted the most attractive offer to Baxter in an auction that drew interest from other private equity firms as well as major players in the biomedical sector such as Thermo Fisher Scientific Inc (TMO.N), the sources said.

The buyout consortium has turned to other private equity firms to help fund the deal as direct lenders, one of the sources added.

There is no certainty that Warburg Pincus and Advent will successfully complete negotiations to acquire the unit and Baxter may still opt to sell to another bidder or keep the business, according to the sources. They requested anonymity because details of the sale process are confidential.

Read more: Reuters