There are two types of frozen plans. Under a “soft freeze”, current participants can continue accruing benefits under the plan while employed, but new employees cannot participate in the plan. Under a “hard freeze”, even existing plan participants cannot accrue further benefits under the plan. The employer is still required to fund the plan. In fact the employer will be responsible for contributions for many years past the date they freeze the plan to fund the liabilities associated with current and future retirees.