Sliding Scale Fees

They're kinda like progressive taxes. Or volume discounts. And they apply to all kinds of products, especially investment ones, where putting to work $10,000 isn't all that different from putting to work a million bucks, depending on the transactor.

Sliding scale fees are really common. The bigger the scale, the smaller the fee per unit sold gets. So a typical mutual fund broker might charge 6% for the sale of anything up to $1,000 worth of NAV purchase. If the buy jumps to $10,000, that fee might be 3%. If the buy jumps to $100,000, it might be just 1%. Way more money put to work "at scale," so the customer pays fewer dollars per unit purchased. Only fair.

See: Breakpoint (not the movie, which sucked).