NEW YORK, April 10 Nasdaq Stock Market Inc. is in talks to buy the Philadelphia Stock Exchange, a published report said Tuesday night.The move to buy the oldest stock exchange in the United States would give Nasdaq a foothold in the options business, the Philadelphia exchange's strength, The Wall Street Journal reported.Options give investors the right but not the obligation to buy or sell a security in the future.The Philadelphia exchange trades more than 7,000 stocks, 2,400 equity options, 17 index options and multiple currency pairs, such as the euro against the U.S. dollar.A Nasdaq-Philadelphia deal may take several weeks to put together, the Journal said.The Philadelphia exchange, founded in 1790, could be valued at $250 million to $300 million, a relatively low price that the Nasdaq could easily absorb, the newspaper said.The exchanges, talking for months, intensified discussions after Nasdaq failed to buy London Stock Exchange PLC in February, the newspaper said.Nasdaq Chief Executive Robert Greifeld has said he wants Nasdaq to become larger in U.S. options contracts.Nasdaq is the No. 2 U.S. stock market by the value of its listed companies. The Philadelphia exchange is the No. 3 U.S. options exchange by contracts traded.Copyright 2007 by UPI