Insurer must cover D&O arbitration defense costs, but split uncertainA Liberty Mutual excess insurer must cover a securities firm’s defense costs in an arbitration brought by a rival brokerage, a Delaware court ruled, invoking a relatively recent legal concept in directors and officers coverage allocation disputes. With the second arbitration covered, StoneX still demanded Ironshore cover defense costs for the first arbitration, for which the settlement was uncovered. The rule helps determine how much of the total defense bill an insurer must pay. Under the rule, a loss is fully recoverable unless the insurer can show that liability for uncovered conduct increased its costs. But she declined to award StoneX all of its defense costs, ruling that factual disputes remained over whether the uncovered arbitration against StoneX itself increased costs tied to the covered arbitration against its employees.