If you are one of the fortunate retirees who does not yet need money from your individual retirement account or 401(k), congratulations.

Now for some bad news: This year’s stock-market decline won’t help when investors over 70 1/2 figure the taxable withdrawals they are required to make by the end of the year.

That’s because “required minimum distributions” these older investors must take from IRAs, 401(k)s and similar tax-deferred accounts are based on the accounts’ values on the previous Dec. 31. In most cases, a withdrawal triggers an income-tax bill, which is why so many people try to postpone them. Also, the longer you can keep your money in one of these accounts, the more you earn from tax-deferred compounding.

This year’s situation seems like a raw deal. A 76-year-old with an IRA valued at $100,000 at the end of last year, for example, is required to withdraw about 4.5 percent, or $4,545, by the end of this year. Even if the account is worth only $80,000 today, he still has to take and figure taxes on the full $4,545, which comes to 5.7 percent of the account’s current value. If the withdrawal were based on the $80,000 value, he’d have to take only $3,636.

Ironically, retirees (with the exceptions noted below) are basing these calculations on a table issued last spring that was meant to reduce the percentage they had to take out each year.

Doesn’t make any sense? Of course not. But tax matters are like horror movies — you have to suspend your disbelief.

And you ignore the rules at your peril, since the penalty for taking out too little is huge — 50 percent of the amount that should have been taken but wasn’t.

Review of rules

So let’s run through the basics.

The first required withdrawal from retirement accounts must be made no later than April 1 of the year after the year in which one turns 70 1/2. If you reached that age this year, you have until next April, though you’d still base the withdrawal on the account value on Dec. 31, 2001.

It might make sense, however, to take the withdrawal by the end of this year, anyway. This is because the three-month grace period applies only to the first withdrawal.

After that, required withdrawals must be made each year by Dec. 31. So a 70 1/2-year-old who waits past Dec. 31 for the first withdrawal will have to take two withdrawals next year. Since withdrawals count as income, making two in a single year could push you into a higher-income tax bracket.

Required withdrawals are calculated using the figures in the accompanying table. Take each account separately, and divide its value on Dec. 31 2001, by the “years” figure in the table corresponding to the age you reached this year. The result is the amount you must withdraw.

For example, if you reached age 80 this year and your IRA’s value was $100,000, divide that by 18.7. The result: You’d have to withdraw $5,348.

The “years” figure is based on life expectancies for people who have reached the corresponding age. The theory is that all the money will be withdrawn by the time you die, if you live as long as the statistics predict. That way, the government finally gets all the tax payments that were deferred in earlier years.

If you have more than one IRA account, you should calculate required withdrawals for each, then add them for a grand total. The withdrawals can be taken from one account, or spread among them in any way you choose, so long as the total is taken. (If you have 401(k)s, 403(b)s or similar accounts, the required withdrawals must be from each account. They cannot, for example, be taken from an IRA instead.)

A few exceptions

Now to those exceptions. The accompanying table is used by everyone except account holders whose sole beneficiaries are spouses more than 10 years younger. They use the Joint Life and Last Survivor Expectancy Table. The fund company, brokerage or bank that handles your account should be able to provide it. All the tables mentioned here can be found on the IRS Website, at www.irs.gov/pub/irs-pdf/p590supp.pdf.

One other thing: The accompanying table, issued in April, reduced the required withdrawals. But it has taken quite a while for the companies that offer retirement accounts to start using it, and you could get an argument.

If you have an IRA, you have a legal right to use the new table rather than the previous ones. But if you have a 401(k) or similar plan, the provider can make you use the older table until 2003.

Regardless of which table you use, this year’s required withdrawal will be based on the account value last Dec. 31. That’s annoying, given that the stock market, measured by the Standard & Poor’s 500, is down 21 percent this year.

But, remember, using the account value from 10 or 11 months earlier works to your benefit in the years when investments are rising in value, so you might have come out ahead in the ’90s.

And if the stock market rebounds in 2003, you might be very happy next year to base your withdrawals on a depressed value recorded at the end of 2002.