Philadelphia Stock Exchange (PHLX), now known as NASDAQ OMX PHLX, is the oldest stock exchange in the United States. It is now owned by The NASDAQ OMX Group. Founded in 1790, the exchange was originally named the Board of Brokers of Philadelphia, also referred to as the Philadelphia Board of Brokers. In 1875, the Board of Brokers changed its name to the Philadelphia Stock Exchange. The exchange merged with the Baltimore Stock Exchange in 1949 and was named the Philadelphia-Baltimore Stock Exchange. It merged with the Washington Stock Exchange in 1954, becoming known as the Philadelphia-Baltimore-Washington Stock Exchange (often abbreviated as PBW). In 1969, the exchange acquired the Pittsburgh Stock Exchange. In 2007, PHLX was purchased by NASDAQ for $652 million.