(Adds background, details; updates shares)
Sept 12 (Reuters) - Nordstrom Inc's founding family has selected private equity firm Leonard Green & Partners to help take the high-end retailer private, according to a source familiar with the matter.
The family and Leonard Green are working on a formal bid that could be submitted in the next few weeks, the source said.
Nordstrom's shares rose as much as 9.6 percent to $49.40 in after-hours trading on Tuesday, valuing the U.S. department store operator at $8.21 billion.
The Nordstrom family group, which owns 31.2 percent of the storied retailer, has been looking to take the company private, as it struggles to compete amid an industry-wide slowdown.
No deal has been finalized yet and talks could still fall apart, the source told Reuters.
Leonard Green would provide the Nordstrom family with about $1 billion in equity to help fund an offer, according to CNBC, which first reported the development.
CNBC also reported that the family was in talks with banks to raise between $7 billion and $8 billion in debt to finance an offer.
In July, Reuters reported that the family had been offering preferential terms to potential equity partners willing to fund a buyout and Leonard Green was one of the firms in talks to partner with the family.
The family was also in talks with private equity firms Apollo Global Management LLC and KKR & Co LLP, sources told Reuters at the time.
Nordstrom and Leonard Green were not immediately available to comment.
Like many mall-based retailers, Nordstrom has been hit by the rise of online shopping and has been seeking to downsize its department store footprint.
The company has also been investing in top locations, and expanding its discount shopping chain, Nordstrom Rack, as shoppers seek more value.
On Monday, the retailer announced the opening of Nordstrom Local, a smaller outlet with no dedicated inventory, but which instead offered customers access to personal stylists and the use of services such as pick-up in-store.
(Reporting by Uday Sampath and Siddharth Cavale in Bengaluru and Liana Baker in New York; Editing by Sriraj Kalluvila)