Merus Capital has just closed its second fund at $43 million and has begun raising a new Merus Capital Opportunity Fund. The latter will invest in the late-stage development of ad-tech firm AdRoll, according to The Wall Street Journal (WSJ).

Earlier this week, AdRoll had secured $70 million in funding, with $10 million raised from Merus. Managing Partner Sean Dempsey said Merus is the ad-tech firm's biggest shareholder. To date, Adroll has raised a total capital of $89 million. The present valuation of the company was not disclosed, the report detailed.

Dempsey explained the reason for the special fund for AdRoll: "It's not the right thing to do to place that kind of investment-$10 million or $20 million-if the size of your fund is $40 million. If our other companies get to that size, we'll raise more opportunity funds in the future."

Merus Capital's second fund has about the same strategy and size with the first. The venture capital firm will continue looking for startups that have both scalable enterprise software and a customer-friendly interface, WSJ reported.