SAN DIEGO -- Federated Department Stores, the parent of Macy's and Bloomingdale's, will announce Monday it plans to buy the owner of the Robinsons-May chain, a deal that could transform several San Diego malls.

Federated Chairman, President and Chief Executive Terry J. Lundgren planned to formally announce the decision at a news conference in New York starting at 11 a.m. Eastern Time, 8 a.m. on the West Coast, according to an advisory released by the company.

Several newspapers and news agencies reported before the announcement that the planned merger, under which Cincinnati-based Federated would pay $36 a share for May Department Stores, which is headquartered in St. Louis, in a transaction worth about $11 billion.

The merger would be felt by shopping malls, clothing makers and media outlets that carry the two companies' advertising.

In San Diego County, Macy's operates seven department stores and one home store. Robinsons-May has seven department stores, along with 10 After Hours Formalwear outlets and three David's Bridal stores.

Macy's and Robinsons-May anchor opposite ends of Fashion Valley, Westfield Shoppingtown UTC, Westfield Shoppingtown North County in Escondido and Plaza Camino Real in Carlsbad.

"I think there's going to be a lot of closures," Gregory Stoffel, owner of Gregory Stoffel & Associates, a shopping center consulting firm in Irvine, told the Los Angeles Times.

Some analysts told The Times the Federated-May combination would spell the end of the Robinsons-May brand, one of the best known in Southern California retailing.

Art Coppola, the president of Santa Monica-based mall operator Macerich Co., which owns 17 shopping centers around the nation with both Federated and May stores, told The Times the deal would be "an absolute windfall" for Southern California shoppers and a plus for his company, because failing stores typically are replaced by those that thrive.

The acquisition would create a company with annual revenue of about $30 billion, a high volume though one dwarfed by Wal-Mart Stores, with its $262 billion in revenue last year.

Federated operates more than 450 department stores in 34 states, Guam and Puerto Rico.

May has 491 department stores including, 47 Robinson-Mays, the stores of the Foley's, Lord & Taylor and Marshall Field's chains, as well as nearly 700 After Hours Formalwear and David's Bridal stores.