The supervisory board of German retail behemoth Metro AG on Friday, Dec. 16, will discuss two offers for department store chain Galeria Kaufhof GmbH after German-American financier Nicolas Berggruen teamed up with New York private equity shop Blackstone Group LP.

The panel is not expected to make a decision Friday on the future of Germany's biggest department store chain but a Berggruen spokesman said the investor made unspecified improvements to the offer following the addition of Blackstone.

The second bid is from Austrian real estate investor René Benko, who was an early favorite.

Although Metro has made several attempts to jettison the Kaufhof stores to focus on its warehouse retailers and foreign expansion, the talks have never reached such an advanced stage. Blackstone had appeared in previous auctions and made an offer for Kaufhof's real estate about seven years ago when Metro was unsure of what it would peddle.

Metro is reportedly asking €2.4 billion ($3.1 billion) for the 139 stores that include Kaufhof outlets in Germany and a handful of Galeria Inno stores in Belgium.

Berggruen wants to revive a years-old plan to merge Kaufhof with his 86 Karstadt department and 26 Karstadt Sport sporting goods stores. Berggruen picked Karstadt out of the bankrupt ashes of conglomerate Arcandor AG last year.

Although a merger of the country's two biggest department store chains may at first raise regulatory issues, attorneys have previously said Berggruen could argue that the überchain would have plenty of competition from smaller clothing and niche rivals, eliminating the concerns.

But his position as owner of Karstadt made Metro initially wary of his intentions. The company didn't immediately grant access to the Kaufhof data room before it was sure the investor wasn't just after corporate secrets.

That's changed with the latest offer.

"Before there were just what I would call talks. What we are seeing now is definitely an offer," said Metro spokesman Kilian Rötzer.

Benko is bidding through his Signa Holding GmbH Austria real estate vehicle and, in addition to his early move advantage, also secured a high-profile adviser when disgraced Porsche Automobilholding SE chief executive Wendelin Wiedeking joined the Signa supervisory board last month.

Wiedeking, who is also an investor in a Signa fund, lost his Porsche job after a power struggle with Porsche family patriarch and Porsche supervisory board chair Ferdinand Piech in 2009. Wiedeking's plans for Porsche to swallow vital parts supplier Volkswagen AG failed in favour of a Piech plan for VW to swallow Porsche.

But that deal is on hold as prosecutors and courts look at the machinations of Wiedeking and former Porsche CFO Holger Härter in connection with the VW approach.