Have you been excluding from taxable income reinvested dividends paid to you by one or more qualifying utility companies? The program that permits taxpayers to exclude up to $750 a year of such dividends (up to $1,500 a year on a joint return) is scheduled to expire at the end of 1985.

Congress could, of course, extend the governing legislation; but in the current climate of "fiscal responsibility" and concern over the size of the federal deficit, I consider that highly unlikely.

The utility-dividend program is really both a tax-deferral and tax-exclusion package. Tax on the dollar value of the dividends (up to the applicable annual ceiling) is deferred until the reinvested shares are sold. At that time, the sale proceeds are taxed at only the capital-gains rate, rather than the ordinary income rate that normally would apply.

But, of course, there are some restrictions. The one you have to watch is the requirement that you hold both the reinvested shares and the original shares on which the dividends were earned for at least a year and a day to qualify for the special capital-gains treatment.

(The 1984 law that reduced the holding period for long-term capital gain or loss from one year to six months did not change the required holding period for reinvested utility dividends, which remains at one year.)

So you don't want to sell any of your shares as soon as the program ends; sale of either the original shares or the reinvested shares would cost you the favored tax treatment. But if you do nothing, you could run into a hassle when you do sell.

That's because your original shares, as well as those in the reinvestment account, will continue to earn quarterly dividends, which in turn will be added to your account. Trying to sort out the shares earned up to Dec. 31, 1985 (which qualify for capital-gains treatment), and the shares earned after that date (which once again are to be reported annually as ordinary income) could present a problem.

I suggest one of two alternatives. If you no longer wish to accumulate shares of a particular utility, write to shareholder services at the company and ask that they terminate your reinvestment account at the end of 1985 and send you a stock certificate for the shares in the account.

(There almost certainly will be a fractional remainder, for which the company will send you a small cash payment. This amount should be reported next year as a dividend subject to normal tax. The loss of capital-gains treatment will be minimal, and it's too complicated to try to buy the missing fraction to round up to a full share.)

Then any time after Jan. 1, 1987, you can sell those shares and be eligible for the tax-favored treatment. Use a basis of zero as your original cost for the shares (also called a zero cost-basis), and report the entire net proceeds as a long-term capital gain. You also may sell your original shares after that date if you wish; the regular capital gain or loss rules would apply to that sale.

If you prefer to continue with the reinvestment program, make a note of the total number of shares in your account on Dec. 31, 1985 (as shown on the fourth-quarter 1985 dividend statement), and keep that memo with your records of the particular stock involved.

When you eventually sell the shares in the account (after Jan. 1, 1987), the number of shares you noted should be reported on IRS 1040 Schedule D with a zero cost-basis. Report the remaining shares separately on Schedule D as either long-term or short-term capital gains (using six months as the benchmark), with a cost basis derived from the amounts reported as ordinary dividend income.

There is a further complication if you already owned some reinvested shares before the tax-favored program started in 1982 and then continued to add new dividends to the same account -- dividends that you excluded from your tax returns.

If you are in that situation, find out how many shares were in the account on Dec. 31, 1981, and subtract that number from the total owned on Dec. 31, 1985, to determine the number of shares that were excluded from income in the intervening years and are to be assigned a zero cost-basis.

Use of a zero cost-basis for shares accumulated during the earlier years -- when they were reported as dividend income on your tax return -- would penalize you by understating your true cost.

Abramson is a family financial counselor and tax adviser.