US wholesale insurance broker AmWINS has been put up for sale by its owners, buyout firm Parthenon Capital Partners and its management, for an estimated valuation of $1.5bn.

Three people close to the matter told Reuters that an auction for acquisition of a majority stake in AmWINS was currently underway drawing interest from buyers including private equity firms.

The estimated enterprise valuation for the firm is expected to be equal to 13 times its $117m earnings before interest, tax, depreciation and amortization (EBITDA) posted for 2011.

About 50% stake in AmWINS is being planned for sale by Parthenon along with management selling some of its ownership, which if finalised will result in offering the buyer control of AmWINS.

The actual stake for sale is open to negotiations, the sources added.

The transaction is provided staple financing support by Goldman Sachs while Financial Technology Partners is serving as adviser to AmWINS on the sale.

A majority stake in AmWINS was bought by Parthenon in 2005 and is currently handling over $6.7bn in annual premiums.

AmWINS owns brokerage, underwriting and group benefit operations across 21 countries and is the largest wholesale insurance broker in the US by premiums placed.