Bessemer Venture Partner has pulled off a “hat trick,” making three major sales of portfolio companies—Sirtris Pharmaceuticals, PA Semi and Gracenote--announced within 12 hours.

In a flurry of deals on Tuesday: pharmaceuticals giant GlaxoSmithKline said it would buy Sirtris Pharmaceutics for $720 million, or $22.50 per share, almost double the company’s closing stock price that day; an Apple spokesman confirmed to Forbes.com reporters that the company had agreed to buy PA Semi, whose microprocessors are expected to land in the iPhone, in a deal believed to be worth  $278 million, and Sony said it was buying music metadata provider Gracenote for $260 million.

Bessemer’s David Cowan attributed the “hat trick” partly to happenstance and partly to the firm’s ability to create its own luck.

“It’s obviously somewhat arbitrary that they all happened on the same day, but it’s not arbitrary that the firm had three good exits,” he said. “We built up a strong portfolio in some areas where there has not been a lot of competition from other venture firms.”

Bessemer’s investments in Gracenote and PA Semi both came in 2004, according to its web site, while Sirtris was funded in 2006.

Beyond the triple play, Bessemer scored in March when BMC acquired Bladelogic for about $800 million and earlier this month when the Nielsen Company snatched IAG Research for $225 million. In February, portfolio company IPC The Hospitalist Company staged an $84.5 million IPO.

Still, Mr. Cowan said 2008 so far is not measuring up to last year, when the company, based in Larchmont, New York, saw Qualcomm buy Flarion Technologies for $600 million in cash and stock and Google pony up $625 million for spam fighter Postini.

“But the year’s still young,” he said.

Sirtris, based in Cambridge, Massachusetts, is developing a pipeline of drugs that target enzymes to arrest diseases associated with aging, including Type 2 diabetes.

Mr. Cowan said that if the three newly acquired companies had anything in common, it was that they all had “swung for the fences.”

Though Bessemer was one of the venture backers of Sirtris, leading a $37 million C round, the biotech’s biggest investor through its IPO was Polaris Venture Partners., which had almost 15 percent of the company going into the offering and more than 12 percent afterward.