A majority of the money in Individual Retirement Accounts is still being held in banks and savings and loan associations. Investments there are both reliable and safe. But as their IRAs grow larger, investors start looking for new worlds to conquer. Obligingly, Wall Street is offering them alternatives:

* A popular investment this year is a zero-coupon Treasury bond or certificate of deposit. You put down a small fraction of the bond's face value and redeem at face value many years later. At current interest rates, your money should triple in around 10 years.

But always ask exactly what net yield you're earning, after paying sales commissions, and compare it with what's available elsewhere. Some sellers have been shaving yields, because investors -- dazzled by the multiplier effect of compound-interest rates -- don't pay close attention to exactly what they're getting.

Don't buy a zero bond unless you expect to hold it to maturity, which can be as much as 20 to 30 years away. The market price of these securities swings wildly up and down. If you should have to sell ahead of time, you could lose quite a bit of money.

* The Cleveland Electric Illuminating Co. has become the first company to establish an IRA for people who buy stock through the company's dividend reinvestment plan. You can use these IRAs only for CEI stock (which now yields 12.2 percent). But you pay no brokerage commissions when you buy the stock, and your dividends are reinvested at no cost.

Treat with great skepticism the IRA-oriented partnerships -- in such things as real estate, oil and leasing -- that promise returns averaging 16 to 21 percent. There is usually less there than meets the eye.

First, that high return is not guaranteed. It's simply what the promoter hopes will be the result. Maybe it will, but then again, maybe it won't.

Second, those yields are often estimated without taking all your costs into consideration. After the promoter deducts his fees and charges, you will walk away with less -- often, much less.

Third, by stating "average" returns, the promoter can materially mislead you. An "average annual return" of 21 percent over 10 years yields exactly the same -- in dollars and cents -- as a 12 percent return compounded annually. Those are simply two different ways of stating the same result. An innocent investor would probably choose the "21 percent" investment, because it sounds as if it yields more. But it doesn't. The promoter has simply pulled the wool over your eyes.

Fourth, there can be a lot of risk in these partnerships. They are simply not as safe as the salesmen maintain. The Petro-Lewis oil-income program, for example, widely sold as a retirement investment, almost went bankrupt, and cost its investors a lot of money.

* To attract customers, some banks now offer insurance plans that promise to complete your IRA if you die or become disabled. IRA disability coverage pays you a monthly income, or makes payments into a special fund, if you can't work. IRA-linked life insurance pays the equivalent of all your IRA contributions up to age 59 or so, if you don't live to make them. Disability plans connected with IRAs invested with insurance companies make payments directly into your IRA.

But if you're short of insurance, $2,000 a year is not going to protect your family. If you need more coverage, buy it separately and in an amount that's large enough to count.

* More banks and S&Ls are now charging annual fees for your IRA. Some have even tried to apply them retroactively. They start low -- in the area of $5 to $7.50 -- but will doubtlessly rise. There may also be fees for closing IRA accounts. If you can, avoid institutions that impose these costs.

Nevertheless, most bank fees are still lower than those charged by brokers and mutual funds. Exception: Some discount brokers offer self-directed IRAs at no fee. You pay only the normal sales commission for buying and selling the IRA investments you choose. No-fee brokers include Charles Schwab & Co. (San Francisco), Olde & Co. (Detroit) and Rose & Co. (Chicago).

IRA trustee fees are tax deductible. But always pay them with a separate check, to make it clear exactly what the money was for. If you add the fee to your $2,000 IRA check, the government might conclude that you put too much money into your IRA this year and assess a penalty. You could, of course, prove that no penalty was owed, but that's a hassle best avoided.