One fund often sells multiple share classes that hold identical portfolios but charge different fee structures. Choosing the wrong class can cost tens of thousands over a holding period.

Common classes:

A shares: front-end load (e.g., 5.75%), lower 12b-1 fee (~0.25%).
B shares: no front load, but a contingent deferred sales charge (CDSC) that declines over 5–7 years, plus higher 12b-1 (~1.00%).
C shares: level load (~1.00% 12b-1) forever, small CDSC for 1 year.
I shares: institutional, no load, lowest expense ratio.

Breakpoints reduce the front-end load at investment thresholds — e.g., 5.75% under $50k, 4.50% at $50k–$100k, 3.50% at $100k–$250k. Rights of accumulation let you count existing holdings toward the next breakpoint.

Class	Front Load	12b-1	Best For
A	5.75%	0.25%	Long horizon, large amount
B	0%	1.00%	Rarely optimal today
C	0%	1.00%	Short horizon (1–3 yrs)
I	0%	0.00%	Institutional / 401(k)