Another, ZestFinance, has focused on the relative niche market of payday loans.

More than 100 online merchants are now using its installment loan product, Buy With Affirm.

The lesson he took from the loan rejection was that traditional banks take an arrow view of loan applicants, and that loans are too hard to get and too expensive for many Americans.

In 2014, its loans reached $8 million, growing gradually.

The most mispriced group in the loan market is financially responsible young people,” he said.

Ananta Pandey, 22, used a loan from Affirm in August to buy an $850 mattress from Casper, an online retailer.

The setup costs for the apartment were a temporary spike in her expenses, and the Affirm loan, Ms. Pandey said, gave her financial flexibility.