Can a plan be terminated?

Although retirement plans must be established with the intention of being continued indefinitely, employers may terminate plans. If your plan terminates or becomes insolvent, ERISA provides some protection. In a tax-qualified plan, your accrued benefit must become 100 percent vested immediately upon plan termination, to the extent then funded. If a partial termination occurs in such a plan, for example, if your employer closes a particular plant or division that results in the termination of a substantial portion of plan participants, immediate 100 percent vesting, to the extent funded, also is required for affected employees.

What happens if your plan terminates without enough money to pay the benefits? Which benefits are guaranteed?