Bain prevailed over other private equity firms in an auction for TOMS and a deal announcement could come as early as Wednesday, the people said. TOMS founder Blake Mycoskie, who has been sole owner, will retain half of the company and stay at the helm.

The sources asked not to be identified because the deal has not been publicly announced. Bain and TOMS representatives did not immediately respond to requests for comment.

TOMS markets itself as an ethical footwear company, donating one pair of shoes to a child in need in a developing country for every pair of shoes it sells. Its offerings include flats, slip-ons, lace ups and sandals.

It also sells eyeware on the same basis, donating one pair of glasses for every one purchased. TOMS says on its website it has given more than 10 million pairs of new shoes to children in need and helped restore sight to over 200,000 people.

Bain's investment will be used to accelerate TOMS' business programme and support its philanthropic activities, one of the people said.

The Los Angeles-based company was founded in 2006 by 37-year-old American entrepreneur Mycoskie after he visited a village in Argentina where children lacked shoes.

Mycoskie, a former contestant on U.S. reality TV show "The Amazing Race," also founded Toms Roasting Co, which donates a week's worth of clean water to a person in need for every bag of coffee purchased.

Bain, a Boston-based private equity firm with more than $75 billion in assets under management, is no stranger to the retail sector, having also invested in discount clothing retailer Burlington Stores Inc, arts and crafts retailer Michaels Companies Inc, and outwear company Canada Goose Inc.

TOMS is the latest in a string of footwear companies to have a pursued a deal. Private equity firm Sycamore Partners LLC is looking to sell luxury shoemaker Stuart Weitzman, while Adidas AG is trying to sell its Rockport shoe business.

(Editing by Soyoung Kim and Cynthia Osterman)

By Greg Roumeliotis and Olivia Oran

Stocks treated in this article : adidas AG, Burlington Stores Inc, Michaels Companies Inc