Definition of 'Back-End Load'
A fee (sales charge or load) that investors pay when selling mutual fund shares within a specified number of years, usually five to 10 years. The fee amounts to a percentage of the value of the share being sold. The fee percentage is highest in the first year and decreases yearly until the specified holding period ends, at which time it drops to zero.
Also known as a "contingent deferred sales charge or load."
Investopedia explains 'Back-End Load'
The back-end load is a type of sales charge that is used with mutual funds that have share classes, which in this case are identified as Class-B shares. Class-A shares charge a front-end load, which is taken from an investor's initial investment. Class-C shares are considered to be a type of level-load fund - no front-end and low back-end loads, but the fund's operating expenses are high. In all cases, the load is paid to a financial intermediary, and is not included in a fund's operating expenses.
In essence, funds with share classes carry sales charges (as opposed to no-load funds). The class you choose is what determines how much and when you pay. In employer-sponsored retirement plans, the loads are generally waived.