Market rumors and speculation has been about that other exchanges would either go private or would merger together after this mega-exchange merger between NYSE Euronext, Inc. (NYSE: NYX) and IntercontinentalExchange, Inc. (NYSE: ICE). The first of the formal rumors in this exchange M&A is now Nasdaq OMX Group Inc. (NASDAQ: NDAQ).

The Wall Street Journal has discussed that private equity player The Carlyle Group LP (NASDAQ: CG) has held discussions with NASDAQ OMX about possibly going private. The talk is that the private equity group approached the electronic trading exchange but it is also said that talks are not ongoing as the two companies did not see eye to eye on price. The tie here is that NASDAQ’s former CFO is now the Carlyle CFO.

We have said that exchange mergers are likely to consider as long investors understand that regulatory risks are present here. The NYSE and Deutsche Boerse were blocked from merging. Other exchange mergers might first be formed by ventures and alliances if they feel that regulators would get involved.

Another issue to consider is that the reason these entities came public in the first place was to unlock the value for the exchange seat-holders and to get access to the capital markets. If a private equity group buys an exchange, chances are high that the exchange will be sold down the road or might even come public yet again in an IPO.

NASDAQ shares are up about 4% at $30.75 at a new 52-week high above the $21.03 to $29.49 share price range of the last year.