Generally pensions operate similar to a 401(k) except for entire companies instead of individuals. Companies are supposed to fund them with the assistance of a

Generally pensions operate similar to a 401(k) except for entire companies instead of individuals. Companies are supposed to fund them with the assistance of actuarial models. The problem is a lot of companies either under-funded or the pensions themselves invested poorly. Ultimately the future cannot be predicted so its likely at least some would fail even if everyone were blameless. This is really a double failure of both the pension plan itself and the insurance that's supposed to provide the public with trust in the system.