ZURICH (Bloomberg) ? Converium Holding AG, the Swiss reinsurer that had a record loss in the second quarter because of reserve additions, may have its financial-strength rating cut by Moody's Investors Service on concern it might fail to boost capital as planned.

Converium, based in Zug, Switzerland, and its German unit Converium Rueckvericherung (Deutschland) AG, may be cut from Baa1 because it is "increasingly unlikely" that the company will raise the full $420 million sought in a share sale, Moody's said in a statement.