Hearing consumers' frustrations may be unpleasant for business operators, but within such feedback lies a hidden trove of information that can be used to improve products and services.

Tokyo-based startup Insight Tech is betting on that concept, making what at first glance appears to be a bizarre offer: Sell us your complaints.

"We basically buy any complaints," said the firm's president, Tomohiro Ito, in an interview with The Japan Times.