Lending Club, the online loan marketplace that's trying to bring Silicon Valley-styled innovation to the financial industry, pulled off a blockbuster public offering this week. In doing so, the company set the bar expectedly high for every other would-be financial disrupter.

The San Francisco-based company raised $870 million from its IPO. Its shares priced at a better-than-expected $15 each late Wednesday, and closed their first day of trading up 56 percent, at $23.43--meaning Lending Club's market cap tops $8 billion. 

"We've had many successes, and we're just getting started," Lending Club founder and Chief Executive Renaud Laplanche told investors and journalists, who gathered Thursday morning at the New York Stock Exchange to watch the company's shares start trading.

It was a star-studded event by financial industry standards. Former Morgan Stanley chairman John Mack, now a Lending Club board member, got up and banged the drum hard for his new industry. Financial technology "will change the landscape" of banking in the next five to ten years, the veteran banker said.

That was echoed by the disembodied voice of Larry Summers, former Treasury secretary and another Lending Club board member, which crackled into the room from a conference call line.

"The point of financial technology should be to help ... consumers lead better lives,"  Summers said. "Too much of financial innovation in recent years has been focused on the convenience of money." 

It's a line that many financial startups are adopting. Lending Club's success has been closely watched by many competitors and other "fintech" startups, which are hoping that this company's outsize public debut will legitimize their industry. (Just ask my email inbox, which overflowed this week with emails from companies eager to weigh in on the IPO.)

"Lending Club is an example of disruption," says Yun-fang Juan, an angel investor and co-founder of Fundastic, which assesses funding options for business owners. "And it's just the beginning. We will see more and more innovations along this line in finance in the next few years."

But many fintech startups face an uphill battle in disrupting the traditional banking industry, which is highly regulated and dominated by a handful of huge, consolidated companies.

That's even obvious in the shift Lending Club has undergone over time. Laplanche founded it in 2007 with an emphasis on peer-to-peer lending, which allows individuals to loan each other money--sort of like a precursor to Kickstarter and other crowdfunding platforms. The company has since morphed into more of an online portal for hedge funds, banks, wealth managers and other big financial investors to finance consumer loans.

But financial startup executives see their opportunity for disruption largely in doing business with lower-income or riskier borrowers, the "underserved" people whom the banks don't want as customers.

Sam Hodges, cofounder of Funding Circle, a small-business loan marketplace, cited the "very large market segments" of "underserved consumers who aren't well-banked. We're doing the same for small-business owners." And, he adds, "these businesses have really powerful network effects and scale benefits once they get going."