Key Elements of the U.S. Tax System

Employer-sponsored Plans

There are two primary types of employer-sponsored plans. Defined-benefit plans generally distribute funds regularly during retirement according to formulas that reflect employees’ years of work and earnings. In defined-contribution plans, of which the 401(k) plan is the most common, balances depend on past employee and employer contributions and on the investment returns accumulated on those contributions.

Individual Retirement accounts

Individuals also may establish their own individual retirement accounts (IRAs). There are two main types: traditional IRAs and Roth IRAs. Like 401(k)s, traditional IRAs allow taxpayers to deduct their contributions, up to a preset limit, from taxable income. Tax liability is only triggered when funds are distributed to the account owners. By contrast, contributions to Roth IRAs and Roth 401(k)s yield no tax breaks when they are made, but distributions to retirees, including accumulated investment income, are tax free.

Participation

Employers are not required to offer their employees retirement benefits, and only about half of all workers are covered by an employer-sponsored plan. Coverage rates are highest for workers ages 45 to 65 and for those earning more than $100,000 (table 1).

Large companies are more likely to sponsor retirement plans than small firms. In 2015, about two-thirds of full-time workers at medium and large firms participated in employer-sponsored plans, compared with about one-third of full-time workers at small firms (EBRI 2018). In 2015, almost all full-time state and local government employees (89 percent) participated in employer-sponsored plans of one sort or another.

Participation in individual retirement accounts is less common than participation in employer-sponsored plans. About 30 percent of taxpayers owned an IRA in 2015, but only about 6 percent contributed to their plan in that year (table 2).