Nasdaq Stock Market, Inc. is close to purchasing the Philadelphia Stock Exchange for about $650 million as it makes a bid to enter the U.S. derivatives trading business, according to reports on Tuesday.

The deal, which has not been finalized, was approved by the Philadelphia exchange board today, Bloomberg reported. Nasdaq voted on the transaction on Monday, according to the Wall Street Journal.

The all-electronic Nasdaq exchange is attempting to expand its businesses beyond stock trading. Under the leadership of its chief executive, Bob Griefield, Nasdaq has also been expanding abroad, with planst to purchase the Boston Stock Exchange and a merger with Norway's OMX AB.

The privately-held Philadelphia exchange currently lists index options, stocks and currency products.

Shares in Nasdaq rose $1.06, or 2.22 percent, to $48.81.

Investment NASDAQ OMX Group NYSE Euronext