According to CoStar Realty Information

The Philadelphia Local American Postal Workers Union, AFL-CIO sold its office building at 1904-10 Arch St. to a private investor known as 1904-1910 Arch Street Associates LP for $3.45 million, or $266 per square foot.

The 12,930-square-foot building is on about a quarter-acre in Philadelphia’s Market Street West area. The buyer already owns close to half of the block, according to the seller.

Carol Huff of Real Estate Investment Strategies Inc. represented both sides in the transaction.

It appears the APWU local sold the building in February 2007 so they could  “find a new building closer to the new processing plant, pay for that new building in full, and to have at least a million dollars to invest when everything is done.”