Sandler O'Neill's Dunne Favors NYSE-Deutsche Boerse

Photo: Oliver Quillia for CNBC.co

New York Stock Exchange

Jimmy Dunne, senior managing principal of Sandler O'Neill, favors NYSE Euronext's merger with Deutsche Boerse ,he told CNBC Thursday.

So does former New York Stock Exchange chairman Richard Grasso. Both were interviewed about how the exchange coped after the Sept. 11, 2001, attacks during live coverage of President Barack Obama's tourof the World Trade Center reconstruction site in lower Manhattan.

The world is "going to evolve and things are going to be different," said Dunne, whose firm is not involved with the Deutsche Boerse merger or the Nasdaqand InterContintentalExchange Inc. hostile offer.

"I think what you’ve got to do is broaden your reach and defend your market share, and you’ve got to do that the most effective way you can," he said. "That’s your first responsibility."

Grasso said the merger with Deutsche Boerse allows the NYSE back into the clearance and depository business, which it "gave away" 40 years ago. "There’s an enormous profitability platform built into the back end," he said.

"The question for owners of the New York Stock Exchange is, do you want to take the premium right now or do you want to embrace the strategy articulated by the management of the stock exchange that down the road there’ll be great incremental value," Grasso said.