U.S. drugstore chain operator Walgreen Co (WAG.N) is exploring the sale of a majority stake in its infusion services business, in a deal that could value that division at around $1.5 billion, according to four people familiar with the matter.

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.

The sources asked not to be identified because the talks are confidential. Walgreen declined to comment while a Bank of America spokesman did not respond to a request for comment.

With a staff of more than 1,600 clinicians, the unit for sale offers infusion services at home and at care centers across the United States. Its infusion therapies are used for medical conditions such as bleeding disorders and serious infections.

Walgreen is currently the largest U.S. provider of home-infusion services. The company solidified that position in 2010 when it swapped its long-term care pharmacy business for the home infusion business of Omnicare Inc (OCR.N).

A deal for Walgreens Infusion Services would come after rival CVS Health Corp (CVS.N) acquired Coram LLC, the specialty infusion services and enteral nutrition business unit of Apria Healthcare Group Inc, for about $2.1 billion in January.

Walgreen has a history of working with private equity. In 2012, Walgreens acquired a 45 percent stake in European health and beauty group Alliance Boots for $6.7 billion, partnering with buyout firm KKR & Co LP (KKR.N) and Alliance Boots Chairman Stefano Pessina, that were left owning the remainder.

Last month, Walgreen said it would buy the remaining 55 percent it does not already own of Alliance Boots for $5.3 billion in cash and 144.3 million shares for a total deal of about $15 billion.