A recent Delaware Supreme Court opinion addressed the titular topic in the matter styled In Re Solera Insurance Coverage Appeals, Nos. 413, 418, 2019 (Del. Oct. 23, 2020).  I’m too busy to provide even pithy highlights, but it’s a consequential decision, so I refer you to the overview provided on the Harvard Corporate Law Blog. 

Kevin LaCroix also provides an insightful and comprehensive analysis of the case on his excellent blog called The D&O Diary.

Delaware’s High Court determined that the costs incurred to defend an appraisal action were not covered by the term “securities claim” in a D&O  policy.