Finance minister Eelco Heinen has given Dutch banks 12 months to improve the way they explain the interest rate paid over savings to their clients.

Heinen has taken the decision following a report by the consumers authority ACM, which said Dutch banks are paying relatively low rates on savings because of the lack of competition.

While there is no evidence of collusion, the four big banks – ING, Rabobank, ABN Amro and  Volksbank – do monitor each other’s rates and adapt their own accordingly, the ACM said. It also said consumers do not shop around for better deals because the big banks only offer savings accounts in combination with regular banking.

Heinen also said he is looking into this construction to assess if it could be banned. However, he warned, a ban could lead to banks imposing charges for savings banks, which could also reduce interest payments.

According to comparison website Sparrenten.nl, Spanish bank Openbank is currently offering 3.65% on some savings accounts while Dutch online bank Bunq is offering 3.36%, with restrictions. But the highest rate paid by one of the big four is 2%, provided by Rabobank. ING and ABN Amro’s best rate is 1.5%.