In the context of pensions, an event that is materially detrimental to the ability of a defined benefit pension scheme (www.practicallaw.com/0-107-7545) to meet its liabilities. A type-A event can either be employer-related or scheme-related. The Pensions Regulator (www.practicallaw.com/9-201-5137) expects parties to apply for clearance (against the possibility the Regulator will use its anti-avoidance powers) only if a type-A event occurs.