NEW YORK (BankingMyWay) -- The good news: new federal rules just now kicking in require full disclosure of fees investors pay for their 401(k)s. The bad news is that many workers will find they’re paying far more than they’d thought.

In fact, a recent AARP study found that most 401(k) participants did not realize they were paying any fees. The annual fees, expressed as “expense ratios,” typically range from 0.28% of the investor’s holdings to 1.38%, according to a report in The New York Times.

Paying an extra percentage point a year can chew deeply into one’s returns over 20, 30 or 40 years. If fees cut your annual returns in a stock fund to 6% from 7%, a $10,000 investment would grow to only $57,435 over 30 years instead of $76,123.

High fees should be of special concern to the investor with conservative holdings, heavy in cash. Since cash holdings like money market funds yield less than 1%, a 1.38% fee would mean losing money every year. Add the damage from inflation, which averages 3% a year over long periods, and your cash holdings face substantial losses.

Investors who want to keep a sizeable cash reserve can’t do anything about inflation, but should look carefully at the new disclosures anyway. If the fees are high, it could make sense to keep your cash outside of your 401(k) -- in an ordinary taxable account at a bank, for instance. Although this would mean paying income tax on your interest earnings, those earnings are so insignificant at today’s low yields as to make taxes a non-issue.

High fee money market funds should be the exception to the rule, as it is: a 2011 study of fund fees from the Investment Company Institute found the median money market fund fee to be 0.22%. Equity funds, on the other hand, had a median fee of 1.35%, while bond funds had a median fee of 0.9%.

What about the asset allocation plan you’ve so carefully set up for your 401(k)?

True, asset allocation -- the mix of various types of stocks, bonds and cash -- is a key factor in investing outcomes. But it’s not necessary to hit your target allocations in each type of account so long as all your accounts satisfy the plan when taken together.

In other words, if you are in your 30s or 40s and intend to have 60% of your holdings in stocks, 30% in bonds and 10% in cash, you don’t need to have the same mix in your 401(k) and in your ordinary taxable accounts. Instead, you could do the stock and bond investing in the 401(k) and keep your cash in a money market, bank savings or certificate of deposit. If things work out, the stocks and bonds in the 401(k) will earn enough to dull the pain from the high account fees, while the cash will escape the potentially higher fund fees and give you the safety you want. Because the stocks and bonds should return more than cash, it makes sense to keep them in the 401(k) to get the tax deferral on gains.

This approach would also allow you to get at your cash for emergencies without the danger of the 10% early withdrawal penalty that applies to most money taken out of a 401(k) before age 59 ½.

Any 401(k) participant facing high fees should consider other action as well. Employees, for instance, can lobby the employer to switch to a provider who charges less. You might also be able to reduce fees by electing cheaper investing options such as index-style mutual funds, if they are offered. If index funds are not offered among your 401(k) plan choices, that in and of itself is a reason to lobby your employer to change providers.

And, if you have retired, quit, been laid off or moved on to a new employer, you can roll over your old 401(k) into an IRA. That could dramatically reduce the fees you pay, as well as giving you virtually unlimited investing options. Any IRA provider -- a brokerage, bank or mutual fund company -- can help with a rollover.