The owner of Hecht Co. announced plans yesterday to fold the Richmond-based Thalhimers department store chain into Hecht's, creating a large regional string of Hecht's stores stretching from Baltimore to Charlotte, N.C.

May Department Stores Co. of St. Louis, which owns Hecht's and acquired Thalhimers last May, said it would turn 15 of the 25 existing Thalhimers stores into Hecht's over the next few months, close seven of the remaining stores and seek buyers for three. The change means the Thalhimers name will disappear after 149 years in business.

Retailing analysts said the merger would allow May Co. to reduce the expenses of operating two similar chains in overlapping geographical areas. In the process, hundreds of Thalhimers's employees will be thrown out of work by the merger, and downtown Richmond will lose its last major department store.

The combination of the two chains will give Hecht's a total of 43 stores and annual sales of about $1.3 billion, making it the largest part of May Co.'s far-flung retail empire. May Co. is the nation's biggest operator of traditional department stores, including the Lord & Taylor and Filene's chains.

The move is the latest step in the transformation of Hecht's from a small Washington chain of discount department stores into a regional powerhouse, with twice the number of stores it had just two years ago.

Hecht's growth has come at the expense of long-time competitors like Woodward & Lothrop and the now-defunct Garfinckel's chain. Hecht's has thrived despite the invasion of its core Washington market by such national chains as Nordstrom Inc. and R.H. Macy & Co.

"This is a very important step and potential for greater profits," said analyst Walter F. Loeb of Loeb Associates in New York.

"It's a fabulous opportunity for Hecht's," said Irwin Zazulia, the president of the Arlington-based chain. "Hecht's will be bigger, stronger, more powerful and better positioned to satisfy our customers."

Among the new markets to be served by Hecht's as a result of the merger are Raleigh, Winston-Salem and Greensboro in North Carolina and Roanoke and Lynchburg in Virginia.

The closing of Thalhimers and the recent demise of the Miller & Rhoads chain leaves downtown Richmond without a major department store and deals a significant blow to the city's efforts to build a retail base through its Sixth Street Marketplace project, an enclosed mall that ran between the two department stores. Richmond City Manager Robert C. Bobb told the Associated Press that the closing was "a heartless and gutless decision to be made during the holiday season. They are truly the grinch that stole Christmas."

May Co. officials said they expected that 750 of Thalhimers's 1,100 employees would lose their jobs as a result of the merger, with most of the cuts coming in buying and administrative areas that will be taken over by Hecht's. None of Hecht's 10,000-plus employees will lose their jobs, the company said.

Hecht's first significant expansion outside the Washington-Baltimore market came when it purchased two Miller & Rhoads stores in the Richmond area and two in the Tidewater area in late 1989. A May Co. spokesman said Hecht's recent growth in Richmond was a factor in deciding to move that brand name farther south rather than operate two chains side by side.

"Hecht's already operates in that market. It's well-known," the spokesman said. "It will make a clearer recognition that it's one company on the part of the consumer."

But Kenneth M. Gassman Jr., a retail analyst at Davenport & Co., a Richmond securities broker, said, "What surprises me is that the Thalhimers name was dropped. That really surprised me. {Hecht's} does not have that same strong consumer franchise" outside the Washington-Baltimore area.

Company officials said the Thalhimers store in downtown Richmond had lost $7.5 million over the past two years, a victim of the economic slowdown that has beset many urban department stores.

In addition to the main store in Richmond, the Thalhimers stores scheduled to be closed include another Richmond location and stores in Virginia Beach and in Raleigh, Greensboro, Winston-Salem and High Point, N.C. Two stores in Charleston, S.C., and a store in Memphis will be sold, company officials said, because they are deemed to be too far outside Hecht's newly expanded market area.

Hecht's will now be the only mid- to upscale department store in Richmond, and will have little competition in many other markets besides discounters and national chains such as Sears, Roebuck and Co. and J.C. Penney Co. "Consumers don't have one choice but Hecht's," Gassman said.

Hecht's total revenue last year was $940 million and its stores had sales of $229 per square foot, the best of May's 14 department store chains. Thalhimers had total sales last year of $445 million, or $153 per square foot. May Co. has 333 department stores, including the Hecht's and Thalhimers stores, and also owns the 3,200-unit Payless shoe store chain.