Tremor Video, one of the largest ad networks for online video, announced Monday that it has raised $37 million in a funding round led by W Capital Partners. At least half of the new funding will be set aside specifically for acquisitions, according to CEO Bill Day.

Well into its growth stage, the company has now accrued over $115 million in capital from VCs like Keating Capital, Draper Fisher Jurvetson Growth, General Catalyst, EDBI, Time Warner and SAP Ventures, most of which had contributed to previous Tremor rounds.

Formerly known as Tremor Media, Tremor Video quickly realized online video to be not only one of the Web’s fastest growing sectors, but also the one most ripe for monetizing via smart, relevant digital ads. As comScore recently reported, 178 million users in the U.S. accessed online video content for the month of June, with each viewer watching an average of 16.8 hours for the month.

In that same report, comScore ranked Tremor as the number one video ad network after Hulu. With three-quarters of a billion video ads displayed in June and a total reach in the U.S. of 20.7 percent, Tremor beat out all its competitors, including Adap.tv, BrightRoll Video Network and Specific Media.

Tremor’s plans to use much of its new capital for acquisitions is not surprising, considering that the company has acquired multiple video ad companies in the past year, including ScanScout and Transpera. Terms were not disclosed for either of the two deals.

The new capital will also be used to invest in Tremor’s new Video Hub analytics platform, which launched in May for company partners but will soon be rolled out to the public.

“We’re becoming more and more of an analytics company and there are other smart people doing interesting things,” said CEO Bill Day.

Tremor also wants to continue expanding internationally.