Health insurance company CZ booked net profit of €315m last year, well up on the €191m booked in 2013.

The company, one of the big four which dominate the Dutch health insurance market, said it would return the money to clients by using it to peg or reduce premiums next year.

CZ used €440m from its reserves – or €147 per client – to keep premiums under control in 2015.

The Tilburg-based company said much of the profit is due to windfall payments, including €180m from its investments.

CZ is the second of the big four to report its 2014 earnings. Last month, Achmea said its net profit had risen to €419m.