The Deerfield, Illinois-based company has hired Bank of America Corp (BAC.N) to run a sale process for Walgreens Infusion Services, which has already attracted interest from private equity firms, the people said this week. On offer is a controlling stake of just over 50 percent in Walgreens Infusion Services, which has annual earnings before interest, tax, depreciation and amortization of around $105 million, one of the people added. Walgreen declined to comment while a Bank of America spokesman did not respond to a request for comment.