Travelers Cos. Inc. said its preliminary estimate of net losses from Superstorm Sandy was about $650 million after tax.

It estimates a gross loss of $1.135 billion excluding expected recoveries from reinsurance, the company said in a statement.

The company also said it intends to resume share buybacks that it had temporarily suspended to assess its exposure to the storm.

Sandy is likely to be the second-costliest disaster in U.S. history, behind only Hurricane Katrina. Industry experts estimate insured losses of as much as $25 billion, excluding claims paid by the federal flood insurance program.

Allstate Corp. said last week that it expects to report October disaster losses of $1.08 billion, mostly due to Superstorm Sandy.