Is there an age requirement for investing in stocks?

Examples of defined contribution plans include Individual Retirement Accounts (IRAs), 401(k), and profit sharing plans. In such plans, the employee is responsible, to one degree or another, for selecting the types of investments toward which the funds in the retirement plan are allocated. This may range from choosing one of a small number of pre-determined mutual funds to selecting individual stocks or other securities. Most self-directed retirement plans are characterized by certain tax advantages, and some provide for a portion of the employee's contributions to be matched by the employer. In exchange, the funds in such plans may not be withdrawn by the investor prior to reaching a certain age—typically the year the employee reaches 59.5 years old—(with a small number of exceptions) without incurring a substantial penalty.