This is a plan where investors make regular, equal payments into a mutual fund, trading account or retirement account, such as a 401k. By using a systematic investment plan (SIP), investors are benefitting from the long-term advantages of dollar-cost averaging and the convenience of saving regularly without taking any actions except the initial setup of the SIP.

Dollar-cost averaging involves buying a fixed-dollar amount of a security regardless of its price. Therefore, shares are bought at various prices over time and the average cost per share of the security will decrease over time. Dollar-cost averaging lessens the risk of investing a large amount of money into a security. In addition to SIPs, many investors reinvest dividends received from their holdings back into purchasing more stock, called dividend reinvestment plans (DRIPs).