Pension plans were originally intended to provide retirement income to long-term
employees on a tax-efficient basis, while helping companies retain employees and keep
direct compensation and taxes lower for the employer. Since the advent of the 401(K) plan
in 1981, there has been a documented, steady decline of traditional DB plans[7]. Unlike
DC plans which specify employer (and sometimes employee) contributions each period,
DB plans promise to provide benefits to retirees based on formulas that typically
consider length of service and earnings. Retirement benefits are funded by actuarially
determined employer contributions that are generally tax deductible up to certain limits.
A trust which invests the assets used to pay benefits to retirees accumulates these
contributions. If the plan assets exceed the actuarially determined liability, the projected
benefit obligation (PBO), the DB plan is overfunded and vice versa.