Insurers will pay $50 million of the $115 million class action settlement against NAB for losses incurred by shareholders in the US mortgage crisis.

The bank says the rest of the settlement will be substantially covered by existing provisions and the case will have an immaterial impact on earnings this financial year.

The group of more than 15,000 shareholders, represented by Maurice Blackburn and funded by International Litigation Funding Partners, bought NAB shares between January 1 and July 24 2008.

NAB said on July 25 that year that it was exposed to $1.2 billion in collateralised debt obligations which included US residential mortgage-backed securities. Its share price fell 13.5% that day.

The settlement includes an $85 million payment and an allowance for interest and costs.

NAB says the settlement “has been reached on a commercial basis and there is no admission of liability”.