Roth 401(k)

The Roth 401(k) is a type of retirement savings plan. It was authorized by the United States Congress under the Internal Revenue Code, section 402A, and represents a unique combination of features of the Roth IRA and a traditional 401(k) plan. Since January 1, 2006, U.S. employers have been allowed to amend their 401(k) plan document to allow employees to elect Roth IRA type tax treatment for a portion or all of their retirement plan contributions. The same change in law allowed Roth IRA type contributions to 403(b) retirement plans. The Roth retirement plan provision was enacted as a provision of the Economic Growth and Tax Relief Reconciliation Act of 2001 (EGTRRA 2001).

In a traditional 401(k) plan, introduced by Congress in 1978, employees contribute pre-tax earnings to their retirement plan, also called "elective deferrals". That is, an employee's elective deferral funds are set aside by the employer in a special account where the funds are allowed to be invested in various options made available in the plan. The IRS sets a limit on the amount of funds deferred in this way, and includes a "catch up" provision intended to allow older workers to save for their approaching retirement. These limits are adjusted each year to reflect changes in the cost of living due to inflation. For tax-year 2015, this limit is $18,000 for those under age 50, and $24,000 for those 50 and over.

Employers may also add funds to the account by contributing matching funds on a fractional formula basis (e.g., matching funds might be added at the rate of 50% of employees' elective deferrals), or on a set percentage basis. Funds within the 401(k) account grow on a tax deferred basis. When the account owner reaches the age of 59½, he or she may begin to receive "qualified distributions" from the funds in the account; these distributions are then taxed at ordinary income tax rates. Exceptions exist to allow distribution of funds before 59½, such as "substantially equal periodic payments", disability, and separation from service after the age of 55, as outlined under IRS Code section 72(t).

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