Say Hello to NYX

John Thain, CEO of the New York Stock Exchange, rang the opening bell Wednesday morning to open the Big Board's first day in its 213-year history as part of a public company.

NYSE Group (NYSE: NYX) will trade under the NYX symbol now that the storied exchange's merger with Archipelago Holdings, the parent company of the ArcaEx electronic trading platform, is complete. The NYSE's 1,366 seatholders received cash and a 70% stake in the new entity, while Archipelago investors retain the other 30% of the shares outstanding.

There were a few dissidents among the NYSE members who believed that Archipelago shareholders were getting too large a stake in the combined entity, or that the member-owned exchange shouldn't become public at all. However, those voices were overruled when the matter was put to a vote in December. Of the 90% of NYSE seatholders who cast their votes, 95% voted for the union.

The market seems to like the pairing of old economy and new economy. Before the deal was announced 11 months ago, one of the NYSE's 1,366 seats sold for a mere $1.62 million. The going price has more than doubled since -- and so have shares of Archipelago.

The trading trade has been hot lately. Intercontinental Exchange (NYSE: ICE) went public four months ago and has gone on to nearly double from its November lows. International Securities Exchange (NYSE: ISE) has doubled since bottoming out in April. And CBOT Holdings (NYSE: BOT) investors who bought during its lows earlier this year after an October IPO have also gotten a pretty hefty return. But the biggest winner has been Nasdaq (Nasdaq: NDAQ), whose stock has actually quadrupled over the past year.

Shares of Archipelago, which will now trade under the NYX ticker symbol, have served readers of the Motley Fool Rule Breakers newsletter service well. The stock has more than tripled since the company was recommended 14 months ago. It has been a major contributor to the 26.1% average gain produced by the 36 past picks -- a gain that has trounced the market's 6.3% average increase during the same time.

Given its rather eclectic means of going public, there shouldn't be a whole lot of fluctuation between NYX's opening price today and the $64.30-per-share price that Archipelago closed at on Tuesday. Where it goes after that will be another story entirely. The ability of the two exchanges to absorb one another will dictate the union's potential, as well as the future upticks and downticks.

It all started with Thain on the bell this morning. Boxing matches start and end that way, too. And NYSE Group has only begun to fight.

Longtime Fool contributor Rick Munarriz thinks that bids and asks are romantic ... in the appropriate context. He does not own shares in any of the companies in this story. The Fool has a disclosure policy. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early.