The figure overshadowed a near doubling of operating profit for the first half of 2015 as the company sought to shake off an ethics fine that led to the resignation of its finance officer last week.

"The negative news on capital overshadows the otherwise strong quarter from an operational perspective," ABN Amro analysts said in a note on the earnings. ABN Amro rates the shares a "Buy".

The capital ratio came in slightly below expectations of ING and ABN Amro analysts at 179 percent, down from 183 percent at the end of the last financial year.

On Aug. 3, the insurer lost a court fight with the Dutch Central Bank over a 22.7 million euro ($25 million) ethics fine after Delta Lloyd executives went outside usual investment procedures to trade on confidential information the central bank had supplied.

Chief Executive Hans van der Noordaa credited a strong performance in the company's life and general insurance operations for the first-half operational improvement.

Delta Lloyd said its gross operational result was 527 million euros ($579 million), up from 269 million in the same period of 2014. Analysts from ING had forecast a gross operational result of 438 million euros.

On the solvency disappointment, Noordaa cited "interest and spread developments" and said the company was managing its capital toward new European Union Solvency II rules that will come into force for the insurance industry next year.

The company said it has sold some of its private equity investments and will seek to sell some of its commercial real estate holdings in order to improve Solvency II ratings.

(Reporting by Toby Sterling; Editing by Biju Dwarakanath and Keith Weir)