A B share is a type of share class for mutual funds. They're known for their back-end sales charges, which are fees incurred after selling the investment.
B Share
What is a B share?
B shares do not have an upfront sales charge, but they have high back-end sales charges (CDSC) when shares are not held for 6–8 years. If they are held for this period, the back-end sales charges decrease and are eventually eliminated.
Compared to A and C shares, B shares have higher 12b-1 fees. Additionally, B shares can be converted to cheaper A shares if held for at least 6–8 years, which is good for investors with little cash and that are investing for the long term.