A few words from Microsoft Chief Executive Steve Ballmer sent shares of Yahoo soaring Thursday.

Speaking at the Gartner ITXpo in Orlando, Florida, Mr. Ballmer said a Microsoft acquisition of Yahoo still “makes sense” for shareholders of both companies.

That was enough to jolt Yahoo shares up $1.20, or 10.2 percent, to $12.95. Yahoo shares have declined 49.5 percent year to date, 17.5 percent worse than the Standard & Poor’s 500.

Last spring, Microsoft proposed a merger that drove Yahoo’s shares into the 20s. Since then, Yahoo’s shares have retreated along with the rest of the technology sector.

Adding to Yahoo’s troubles is the regulatory scrutiny that has stalled the Internet company’s planned co-operative advertising venture with Google. That deal had been expected to pump up to $800 million in additional search advertising revenue into Yahoo.

Dow Jones quoted Mr. Ballmer as noting that Yahoo management had turned down an offer of $33 per share.

"Probably still think it's worth at least as much today,” he said with a laugh.

But Microsoft’s public relations department cleaved to the same official stance the company has maintained since negotiations broke off.

“Our position hasn’t changed,” the statement said. “Microsoft has no interest in acquiring Yahoo!; there are no discussions between the companies.”