By Maarten van Tartwijk 

Dutch food retailer Royal Ahold NV and Belgium's Delhaize Group confirmed Tuesday they are in talks about a possible near-$26 billion merger that could create one of the largest supermarket operators in the U.S.

Despite being based in Europe, both companies generate about 60% of their sales in the U.S., primarily along the East Coast. Ahold operates the Stop & Shop and Giant chains, as well as online grocery store Peapod, while smaller rival Delhaize operates the Food Lion and Hannaford banners.

No financial details of the potential deal were disclosed and the companies cautioned that the talks might not result in any deal. However, based on closing share prices Friday--before renewed speculation about a deal surfaced--the merged company would be valued at EUR22.91 billion ($25.79 billion).

Ahold and Delhaize, like midmarket retailers world-wide, find themselves caught in a squeeze between discounters like Wal-Mart Stores Inc. and Costco Wholesale Corp. and high-end grocers like Whole Foods Market Inc. The two European companies have been thinking about a combination for years, reportedly having held talks in 2006, as they seek greater scale and cost savings to take on the competition.

Still, some analysts are skeptical about the potential tie-up. "Cost savings in retail acquisitions or mergers are highest when there is a large overlap and local scale economics improve," analysts at Bernstein said in a note on Monday. "In this case there is very limited local overlap.... We think this is a bad deal for Ahold investors."

David Payne, an analyst at Nomura, agreed that there are relatively few synergies between the two companies' U.S. operations. "We do believe there is at least shareholder appetite for the simplification that combination (and later, perhaps, separation of U.S. and European operations into two new companies) would bring," he said in a research note.

A combination would create one of the largest food retailers in Europe and the U.S. with around EUR54 billion in annual sales. Based on recent estimates by Morgan Stanley, a combination would have a market share of around 4.2% in the U.S., making it the country's fifth-largest food retailer.

Both stock soared on deal speculation Monday, with Delhaize up 14.5% and Ahold up 5.5%. In morning trading Tuesday, Delhaize was up 1.1% to EUR83.84 and Ahold was up 1.8% to EUR18.51.

Ian Walker contributed to this article.

Write to Maarten van Tartwijk at maarten.vantartwijk@wsj.com

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