Class A shares charge an upfront sales fee, or front-end load, that is deducted from your initial investment.  Class B shares have a back-end or contingent deferred sales charge. This fee is paid when you sell shares for a specified year after the original purchase. Someone who has limited cash will be good for these kinds of shares. B shares are slowly disappearing from the mutual fund industry because of more regulatory focus on fees. Many funds companies are dropping these fees and shrinking the class offerings to compete with exchange-traded funds. Class A shares would be best for those looking to plan their retirement because they offer costs that decline over time. Also good for those looking to invest one lump-sum amount, which is enough to qualify