Shareholders of Sears, Roebuck and Co. and Kmart Holding Corp. agreed Thursday to merge the chains into the nation’s third-largest retailer, the two companies said in a joint statement.

Shareholders of both companies approved the merger separate votes on Thursday, according to the statement, consummating a deal announced in January. The combined company, with 3,500 stores and $55 billion in annual sales, is now called Sears Holdings Corp. It’s headquarters are at Hoffman Estates, Ill., which is also Sears headquarters. Kmart is headquartered in Troy, Mich. On Monday, the new company will be listed on the Nasdaq National Market under the ticker symbol “SHLD.”

The new company is chaired by Edward S. Lampert, the financier who engineered the deal.

“This new enterprise will seek to leverage the combined strengths of Sears and Kmart to create greater long-term value than either could have generated on a stand-alone basis,” Lampert said in the statement. “Sears Holdings plans to offer customers a new, more compelling shopping experience with a differentiated and expanded product range.”

The holding company said it will retain both the Sears Roebuck and Kmart names as separately run brands.

Last year, Sears bought 50 Kmart stores in a transaction that was a precursor to the merger.

This spring, it is opening the first 25 “Sears Essentials” stores, including three in the Washington area, in Clinton, Hyattsville, and Warrenton. Those stores aim to combine some of the most desirable elements of Sears and Kmart.

They are located in strip shopping centers, all on one level, and are meant to be more convenient to get in and out of than traditional Sears stores.

Their checkout lines will be in one central place, rather than spread out as at department stores. However, the stores will still carry product lines that are Sears mainstays, including Kenmore appliances and Craftsman tools.

JCK