ING plans to list its insurance and investment management operations in two public offerings (IPO) as part of European Commission approval for state aid received in 2008 during the credit crisis.
ING Chief Executive Jan Hommen said he did not rule out that its US closed book of variable annuities, which caused the charge, may be excluded from the listing.
ING shares fell 2.6 percent to 6.15 euros by 0846 GMT, underperforming the STOXX Europe 600 insurance index, which was up 0.8 percent.
Analysts said they were surprised by the charge and its size but that it was part of ING's IPO plans.
ING will take a charge of between 0.9 billion and 1.1 billion euros on its closed book of US variable annuities in the fourth quarter because investments linked to the products had fallen in value, ING's US annuity business CEO Mike Smith said.
"We set aside resources for the likely difference for what we have in their account and what we ultimately need to pay the policy holders. The increase of reserve which is the source of the charge is really the way to think of the loss," Smith said.
More customers than expected were exercising their policy, resulting in the charge, he said.
It was the third time ING took a charge on the insurance products, after a 975 million euro charge last year and 343 million in 2009 and Smith said more charges or positive revaluations were possible.
Almost 500,000 US customers had a variable annuity, and the total value for policy holders was currently about $45 billion, Smith said.
ING still needs to pay back 3 billion euros of state aid plus a 50 percent premium and wants to do it by May 2012 but an ING spokesman said the charge would not impact the time schedule for repayment.
Hommen said last month repayment could be postponed because of market uncertainty and new capital requirements.
