"Rapid changing of managers tends to reduce returns," he said.

These funds have sales fees, albeit hidden ones, that reduce returns over time.

Usually, these funds have a level load, which means there are hidden fees that reduce returns.

Resolving them might actually give a lift to the dollar, which would then reduce foreign returns.

It may seem odd to think of taxes as reducing annual returns that are already negative.

Over time, they say, that reduces returns for investors who build a portfolio of such funds.

Paying a sales load (41 of the 56 funds charge one) will also reduce returns.

Fees and commissions can be high, which could further reduce returns.

These fees, charged by about a third of taxable money funds, reduce returns.

In addition to reducing returns, retailers have found another benefit.