A consortium of Ares Management LLC and the Canada Pension Plan Investment Board is in advanced talks to acquire upscale U.S. retailer Neiman Marcus Inc from TPG Capital LP, Warburg Pincus LLC and Leonard Green Partners LP, two people familiar with the matter said on Sunday.

A deal for Neiman Marcus could be announced as early as this week and would mean that the company would not proceed with its plans for an initial public offering, the people said, asking not to be identified as the negotiations are confidential.

One of the people said the deal would likely value Neiman Marcus at around $6 billion, but cautioned that negotiations had not been finalized and that talks could still fall apart.

Neiman Marcus, Ares, TPG and Warburg Pincus declined to comment. Spokespeople for Leonard Green and Canada Pension Plan Investment Board did not immediately respond to requests for comment.

Neiman, which operates 41 namesake departments stores, Bergdorf Goodman, as well as the lower-price outlet chains Last Call and CUSP, was acquired by TPG, Warburg Pincus and Leonard Green in 2005 for $5.1 billion.

The Wall Street Journal reported earlier on Sunday that Ares and the Canada Pension Plan Investment Board were in the final stages of negotiations to buy Neiman Marcus.

(Reporting by Greg Roumeliotis in New York; Editing by Nick Zieminski)