Superstorm Sandy is expected to result in a net negative impact of about $333.1 million for Validus Holdings.

Validus says Sandy will cost Flagstone Reinsurance Holdings $39.1 million, but this impact will not affect the fourth quarter results at Validus since the Pembroke, Bermuda-based company’s acquisition of Flagstone was completed after the storm.

Validus reached an agreement in August to buy Flagstone for about $623 million in cash and stock. The deal was completed Nov. 30—about one month after Sandy struck the Northeast.

The $333.1 million tally is after reinstatement premiums and reinsurance, retrocessional and other recoveries, says Validus.

About $256.2 million will be felt in the Validus Re segment and $79.6 million will come from the Talbot segment, a specialty group operating in the Lloyd’s insurance market through Syndicate 1183.

“Hurricane Sandy was a large, complex loss event impacting our business across all of our operating segments and through multiple classes,” says Validus CEO Edward J. Noonan, in a statement. We see this as being both unique and difficult for our clients to reserve.”

Noonan says Validus’ estimate is based on industry-wide losses of more than $25 billion, which, he adds, “exceeds industry loss estimates implied by the aggregate losses reported to us to date by our ceding clients.”

Navigators Group

Between $18 million and $25 million of losses are expected from Sandy at the Navigators Group.

The New York-based specialty insurer says the preliminary tally includes estimate of claims and claim expenses, reinsurance recoveries, and reinstatement premiums.

Navigators says actual losses from Sandy will vary—maybe significantly—from its preliminary estimate.