More than 30,000 car owners will receive more than $15 million in refunds after an investigation uncovered improper financing of tyre and rim insurance premiums by some of Australia’s largest car financiers.

The Australian Securities and Investments Commission (ASIC) inquiry began when BMW Australia Finance notified the regulator of a National Credit Code breach and repaid $1.39 million to 2466 customers.

Other companies that will refund more than $1 million include Esanda ($5.3 million), Capital Finance Australia ($2.7 million), Yamaha Motor ($1.48 million), BOQ Credit ($1.26 million) and Toyota Finance ($1.01 million).

The credit code allows the financing of car cover premiums for one year only, ASIC says.

Any longer and customers can pay undue interest on premiums and be unfairly locked into long contracts with one insurer.

“These businesses were quick to respond once it was brought to their attention,” ASIC Deputy Chairman Peter Kell said.

The financiers have taken steps to repay the money and will change their systems to prevent further breaches.

“If we find there are car financiers that have failed to respond to this issue, we will act quickly and decisively with strong regulatory action,” Mr Kell said.

Tyre and rim insurance covers wheel damage including punctures and blowouts. ASIC says such damage is not usually included in standard comprehensive motor vehicle policies.