BOSTON, United States — Private equity firm Thomas H. Lee Partners LP is in advanced talks to acquire the enterprise business of eBay Inc for close to $1 billion, according to people familiar with the matter.

Thomas H. Lee has so far outbid other parties in the auction for the business, though disagreements over price persist and there is no certainty that a deal will be reached, the people said this week.

The sources asked not to be identified because the negotiations are confidential. A spokesman for Thomas H. Lee declined to comment, while eBay did not respond to a request for comment.

eBay's enterprise business, formerly known as GSI Commerce, helps retailers around the world beef up their online presence and e-commerce capabilities. eBay said in January that it would explore strategic alternatives for the unit, which does not fit neatly with its PayPal and marketplace divisions.

GSI Commerce was acquired by eBay for $2.4 billion in 2011. It has lost customers and seen sluggish growth in the past few years as its clients move their online operations in-house.

Toys “R” Us Inc, a client of GSI Commerce since 2006, announced on Thursday it was launching its own online platform, a move that could take away more business from the unit.

Based in Boston, Thomas H. Lee has raised approximately $21 billion of equity capital and invested in more than 130 portfolio companies with an aggregate value of over $150 billion since it was founded in 1974.

Bloomberg News reported last month that Thomas H. Lee was one of the remaining bidders for eBay's enterprise unit.

By Liana B. Baker, Greg Roumeliotis; editor: Andrew Hay.