BPG Properties Ltd., a privately held Center City firm with $4 billion in real estate investments, said yesterday that it had acquired 22 apartment complexes in Pennsylvania for $314 million. It was the largest transaction in the firm's history, BPG said.

The company bought the apartment complexes - which include four in the Philadelphia suburbs - from National Properties Inc., of Malvern. The local apartments are in Exton, East Norriton, Phoenixville and Norristown. The deal also includes complexes in the Harrisburg, Reading and Allentown areas.

BPG officials said that it was "extremely rare" to buy so many apartment complexes in Pennsylvania at one time and that the deal was a substantial boost to the company's real estate portfolio.

Jeff King, president of National Properties, said he and his partner were liquidating their company so they could retire after 35 years.

The housing boom earlier in the decade hurt the rental market because people could buy a home for what they could pay renting, King said.

But he said the apartment business had recovered in the last 18 months, "much to my surprise." He said that National Properties employed 160, of whom three-quarters had joined BPG.

With the deal, BPG now owns 24,000 apartments in 110 complexes in the United States. It also owns office buildings, shopping centers and factories.

Joseph Mullen, a senior vice president of BPG who oversees investments in multifamily properties, said the Pennsylvania apartment market had been steady and did not suffer from oversupply. The 3,437 newly acquired apartments are 94 percent occupied, BPG said.

Mullen said BPG intended to spend about $5 million renovating its new complexes. The Dogwood Gardens, a 144-apartment complex in Norristown, will get a new roof and a more modern look, he said. About half the acquired complexes were built before 1980.

BPG, the former Berwind Property Group, employs 110 in its Center City headquarters, executives said.

Contact staff writer Bob Fernandez at 215-854-5897 or bob.fernandez@phillynews.com.