A survey by the Dutch financial regulator (DNB) has found that the country’s pension funds are increasingly embracing the principle of sustainable investing.

Nearly 90% of the more than 200 pension funds surveyed have put in place a green investing policy to some extent, while more than 10% – typically the larger schemes – have fully integrated the concept into their investment strategies.

Frank Elderson, DNB supervisory director for pension funds, said: “The sector has a number of leaders, both larger and smaller schemes, that stand out internationally.”

The regulator said the proportion of schemes citing sustainability in their investment beliefs had increased from 45% three years ago to 74%.

It added that an increasing number of Dutch pension funds were recognising the opportunities offered by sustainable investing, even those that had made the investments initially for “reputational reasons”.

The watchdog acknowledged, however, that separate studies had failed to find a clear correlation between sustainability and returns.

DNB cited the €372bn civil service scheme ABP and the €179bn healthcare scheme PFZW as particular examples of pension funds with integrated policies for sustainable investing.

It said smaller and average-sized schemes had found it difficult to develop their own policies due to the cost of tailor-made approaches and suggested that co-operation might be the answer.

It also called on pension funds to be more transparent about their sustainability criteria.

The regulator called for further studies into sustainability criteria and investment policy, including tests comparing the effects of green policies and less-than-green ones.

It also took pains to emphasise that it would allow pension funds to incur higher costs for sustainable investments, “as long as they can provide a proper explanation”.

The Dutch Pensions Federation said the regulator’s survey “seamlessly” matched the conclusions of five surveys it conducted between 2003 and 2013.