In March, Visa challenged the startup community to come up with new ways to engage and inspire millennials, encourage affluent consumers to take advantage of Visa Signature credit card rewards, and increase adoption and usage of Visa Checkout, an online-payment platform that is approaching its one-year anniversary.

The company selected three winners yesterday -- one for each marketing category -- out of a pool of 396 entries. Fifteen finalists presented their ideas to a panel of judges from Visa's marketing and communications team at the financial firm's innovation center in San Francisco, and three walked out as winners.

"My only regret is that I want to do things with all 15 of them," said Shiv Singh, senior VP-global head of digital and marketing transformation at Visa. "We're going to find ways to do more and more with all of them."

Each of the startups came up with business solutions that go beyond Visa and can help the firm's bank and retail partners as well. The company is preparing $50,000 pilot programs with each of them.

Virgil, which won the challenge to inspire millennials, is a mobile career-building platform that helps job seekers build career skills and find jobs at companies that suit them. It also allows employers to understand what it takes to keep their young workers around for a long time, solving a problem for companies whose millennials employees are walking out the door shortly after they're hired.

Another winner, Flag, came up with a new way to reward Visa Signature consumers. The young company is creating a photo printing app, which prints and ships smartphone photos for free. The service is free to use because brands sponsor the photos with ads and promotions on the back of the pictures. It's a new way for financial firms, which are among the biggest direct mailers, and other marketers to deliver ads that won't be tossed in the trash.

"It's just pure genius," said Mr. Singh. "Now, all of a sudden, you have an opportunity to send direct mail that people care about."

Charged with pushing Visa Checkout usage, the third winner, Lisnr, built a tool that sends data over a sound system. It's a high frequency audio file that works with any speaker, allowing marketers to deliver geo-targeted ads without beacons or other hardware. The platform works through apps that consumers already have installed on their phones, such as the Visa app. Visa plans to use the technology to deliver mobile alerts that encourage consumers to shop at merchants where Visa Checkout is accepted. The company may also leverage the tool at major sponsored events such as the Super Bowl and the Olympics.

The startup challenge, a first for the marketer, is helping change the culture within Visa, bringing the company closer to the startup world and encouraging innovative thinking, according to Mr. Singh. Visa worked with Kite, a company that connects startups with agencies and brands, throughout the contest to engage and learn from the finalists. The startups interacted with the company's 200 interns and presented to clients. To emulate startup culture, Visa also flew in finalists from out of town and housed them at an Airbnb dubbed "The Startup House."

"This isn't just about finding partners to do pilots with," said Mr. Singh. "It's about taking every opportunity to bring in the best of the best startups, expose them to our constituents and have them influence our culture."