Pensions & Investments has reported more than $200 billion in defined benefit liabilities moving to insurers from plan sponsors over the past decade. The market has had more than 30 insurance companies participate. However, the majority of the buy-ins and buyouts have been concentrated in five insurers. In addition to liability transfers, more than $100 billion of longevity risk has been assumed by insurance companies. Prudential accounts for almost one-third of all activity.