When it comes to keeping the New York Stock Exchange trading floor open, Robert Greifeld makes a very unlikely savior.

As the chief executive of the all-electronic Nasdaq exchange, he has questioned whether a physical place where actual human beings come together to buy and sell stocks is even necessary, dismissing the 219-year-old New York Stock Exchange, a capitalist icon, as “a stage prop” that ought to be taken apart “board by board.”

Now, though, with the Nasdaq OMX Group and the IntercontinentalExchange in a fierce fight with Deutsche Börse to buy the Big Board, and its parent company, NYSE Euronext, Mr. Greifeld has abruptly reversed course, insisting he will not only keep the floor open but reverse its long decline and reinvigorate it.

Although it might seem largely symbolic — only about 1,200 traders remain on the floor, down from 2,000 at its peak — both bidders are promising to keep it open, a rare point of agreement and a nod to the high-stakes public relations battle now under way.

Behind the scenes, however, a more fundamental shift is being proposed.

Read the full article by Graham Bowley in The New York Times.