FORTUNE -- Earlier this year we reported that Bill Trenchard, co-founder of LiveOps and Jump Networks, had agreed to spend the summer making investments for First Round Capital. Basically a feeling-out period for both sides.
Well, it seems that the experiment felt pretty good.
First Round announced today that Trenchard is joining the firm full-time as its third West Coast partner, bringing the overall partnership to eight. And, since the partnership now has grown by 15%, First Round also has expanded the size of its fourth fund from $135 million to just over $155 million (one new investor, plus increased commitments from existing LPs).
"We had no plans to add another partner to the firm at this time," explains First Round co-founder Josh Kopelman. "But we had this list of three to five people who, if they became available, were the type of people we'd bust the budget for -- people we just had to have. Bill was on that list."
Kopelman adds that his relationship with Trenchard goes back to when he was launching a business just out of college, and when Trenchard was still an undergrad at Cornell University.
"Bill was doing web development while still in school, and I was his first and largest customer," Kopelman says. "Figured it was better to outsource in Ithaca than an India, and the rates were pretty comparable."
Trenchard and First Round also would co-invest on several deals, including HomeRun (acquired by Rearden Commerce).
Prior to joining First Round, Trenchard had been an angel investor and founding partner of Founder Collective (where he'll remain a limited partner). He currently sits on the boards of Readyforce, LiveOps, Looker and Samasource.
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Noted seed investor switches shops.
Bill Trenchard is planning to spend his summer making investments for First Round Capital, Fortune has learned. He will work out of the firm's West Coast office for at least the next several months, after which he may remain with First Round or move onto another endeavor.
Trenchard most recently had been investing on behalf of Founder Collective, where he will remain listed as a founder partner. His deals have MOREDan Primack - Jun 5, 2012 2:49 PM ET
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