Google co-founder Larry Page said Thursday the Internet search leader opposed a Microsoft-Yahoo deal because it would monopolize the online communications market, stifle innovation and curb competition.

But he discounted the idea that an advertising deal between Google and Yahoo would present any potential antitrust problems.

Page said a successful Microsoft-Yahoo deal would have closed “a lot of things that are really important … like instant messaging.”

“Now, if you put 90 percent of the communications all in one company … that’s really a big risk, especially one (Microsoft) that has a history of doing bad stuff,” he said.

While he said Google has a large advertising share, “there are ways in which to structure a deal with Yahoo that will be reasonable … especially given the alternatives they have, which aren’t great either.”