Insurance giant Nationale Nederlanden (NN) is facing a claim for €3.2 billion over alleged hidden charges in its investment products.

The case is being brought by Wakkerpolis, which represents some 4,400 aggrieved NN customers, along with the consumer rights watchdog Consumentenbond. Altogether around half a million people took out similar products from various insurers between 1990 and 2008.

The so-called ‘woekerpolis’ affair was brought to light in 2006 by TV consumer show Radar, following an investigation by the Dutch financial markets regulator AFM. The AFM said hidden costs meant many customers paid more to cover their investments than they earned from them.

Insurers used the investments as endowments to underwrite other financial products, such as mortgages and pensions.

Last year the consumer rights tribunal Kifid ordered NN to repay upfront costs that it said had been concealed from customers when they signed the contract. The average repayment is around €3,500. NN has appealed against the decision.

If Wakkerpolis wins its claim the insurer is expected to settle the case to limit its liabilities to far less than the €3.2 billion claimed.