FastPay has received $15 million in growth equity funding from Oak HC/FT, a new $500 million venture capital fund that invests in health care and financial services technology.

The money will go toward further developing FastPay’s online lending platform, building more financial technology products and doubling its 40-person team over the next 18 months.

The Beverly Hills company helps digital media businesses with their cash-flow problems, which includes invoicing advertisers and financing loans for startups that can’t afford to wait months before getting paid for a campaign. FastPay said it has originated $500 million in loans since launching in 2009 and charges 1 percent to 2 percent a month for its lending service. It’s an appealing alternative for startups that want to avoid relying on VC funding.

Founder and Chief Executive Jed Simon said the company never set out to raise a lot of venture money. But as the online lending marketplace continued to grow, it became a smart decision to raise additional equity to compete with industry veterans.

“LendingClub and Prosper, business-to-business organizations like OnDeck and just the general sector growth of digital media and advertising – the opportunity set in front of us seemed so substantial,” he said.

Thursday’s financing brings FastPay’s total equity funding to date to $19 million. FastPay is Oak HC/FT’s first fintech investment.

Staff reporter Melissah Yang can be reached at [email protected]. Follow her on Twitter @MelissahYang for the latest in L.A. tech news.