SCHENECTADY, N.Y. -- Price Chopper Supermarkets here said it has completed its acquisition of Wonder Market Cos., Worcester, Mass., operator of 12 Big D supermarkets in Massachusetts. Under terms of the agreement, Price Chopper purchased the operating company and leased back the 12 Big D stores, according to Hunneman Commercial Co., the real estate broker that handled the transaction. The acquisition expands Price Chopper's presence from western Massachusetts, where it operates six stores, into the central part of the state and adds an estimated $160 million to its $1.5 billion sales base. Price Chopper operates 79 stores in New York, Vermont, Pennsylvania and Massachusetts. The chain's executives previously told SN they plan to convert the stores to the Price Chopper banner within six months to a year after the deal closes. They said they will either remodel or replace the stores, which range from 20,000 to 40,000 square feet, while adding the latest technology, new marketing programs and expanded product lines to the stores. According to Neil Golub, chairman and chief executive officer of Price Chopper, "We feel that the purchase of these stores is beneficial to all parties and to the communities involved." Wonder Market Cos. was founded in Clinton, Mass., in 1923 by Nathan Gould, father of Calvin Gould, Big D's president and chief executive officer.