Final answer:
A provision in pension plans referring to non-forfeitable employer contributions is known as vested benefits. Pensions are decreasing in prevalence, being replaced by defined contribution plans like 401(k)s and 403(b)s, which are portable and offer tax advantages.
Step-by-step explanation:
A provision in pension plans referring to the money contributed by the employer that has been placed in a pension fund and cannot be forfeited for any reason is known as vested benefits. These are contributions that the employee is entitled to, even if they leave the company before retirement. This is distinguished from pension insurance, where employers pay a fraction of the pension contributions to the Pension Benefit Guarantee Corporation to protect against company bankruptcy. Compared to traditional pensions, defined contribution plans like 401(k)s and 403(b)s are becoming more prevalent. These plans involve regular contributions from both employer and employee and offer advantages like being tax deferred and portable.