Question: In a recent column you mentioned that Series E savings bonds reach maturity 40 years after the issue date. In redeeming E bonds issued in April 1943 and held until maturity without reporting annual interest, would there be a profit or loss in regard to actual purchasing power?

Answer: Your question was fascinating; tracking down the answer led me into some interesting byways. First stop was the Treasury Department, where I learned that a $100 face amount bond bought in April 1943 for $75 would have paid $399.80 on maturity in April 1983, including $324.80 in accumulated interest.

On to the Bureau of Labor Statistics, the federal agency that keeps the score on the cost of living. Using a base year of 1967, they calculate that $1 in 1943 had a value of $1.919 compared with a 1967 dollar. On the same comparative base, $1 in April 1983 is worth just 33.8 cents.

Using that 1967 dollar as a standard, we find that the $75 invested in April 1943 had a purchasing equivalent of $143.93. The April 1983 payoff was worth just $135.13 in terms of that same 1967 dollar.

So what you got back in 1983 would buy just 93.89 percent of what the $75 you paid in 1943 would buy--a small loss in terms of purchasing power even though the number of dollars is greater.

But wait--we haven't figured in the impact of the tax bite you have to pay on the $324.80 of accumulated interest. Let's assume a marginal federal tax bracket of 26 percent. (There is no state tax on federal bonds.)

After subtracting the tax of $84.48, you now have just $315.32 left for your original $75 investment of 40 years ago. And in those old 1967 dollars, that $315.32 has only $106.58 in purchasing power, compared with the value of $143.93 in those same 1967 dollars that your original $75 could command.

We could, of course, make the same kind of calculations for other investments; the results might be better or worse, depending on how well the one you picked made out during the intervening 40 years.

And in fairness to present Series EE bonds, I should point out that they now offer a variable market rate tied to Treasury bill rates and changed every six months, so bonds bought now should provide improved protection against inflation (assuming that interest rates track with inflation, as they have in recent years).

In any case, thank you for getting me started on a fascinating chase. I hope you find the answer as interesting as I found the question.

Q: Questions on estate taxes seem always to be related to "spouses." What about the amount that may be bequeathed to an only child (an adult)? In such cases, how may estate taxes be minimized?

A: Under the Economic Recovery Tax Act of 1981 (ERTA), there is no limit to the value of assets that may be transferred to a spouse free of federal estate tax.

The dollar limit on bequests to other heirs was increased by ERTA, but the increase is being phased in on an annual basis. For deaths occuring this year, $275,000 may be passed without tax liability.

Here are the increasing ceilings for the following years: 1984, $325,000; 1985, $400,000; 1986, $500,000, and 1987 and thereafter, $600,000.

If you expect your net estate (after expenses and charitable bequests) to exceed the amount for whichever year you plan on dying (I can't think of a more delicate way to phrase that), the simplest way to reduce the estate-tax bite is to give some of your assets to your child while you're still alive.

There are other ways--the use of trusts, for example--but you should have professional help and advice if your estate is large enough to warrant concern.