Today we turn to another chapter in the long-running saga of the AT&T divestiture and the tax implications arising from that quintessential -- and questionable -- quagmire. I refer particularly to the 7 percent of Pacific Telesis stock that the IRS had ruled represented a taxable dividend rather than part of a tax-free exchange.

Let me quote first from my column in these pages of March 11, 1984: "The Internal Revenue Service has taken the position that a small portion of the Pacific Telesis distribution represents a taxable dividend that should be reported on your 1984 tax return.

"Corporate counsel for AT&T differs with this ruling, however, and believes that the entire distribution is a tax-free exchange which has no present tax impact. . . . You should discuss this question with your own tax adviser."

In answer to a question from a reader, I expressed my own opinion in this column on April 23, 1984: "When there is a clear rule on how to handle a particular tax situation, that rule should be followed. But this difference of opinion between the IRS and AT&T may go unresolved for some time.

"As a tax consultant, my position has been that whenever there is an unresolved question, the taxpayer may properly take the route that provides the lower tax. For most taxpayers, establishing a higher cost basis for computing capital gain or loss on a later sale is a better tax strategy than reporting and paying tax on current dividend income."

But on March 24, 1985, I had to report that " . . . the IRS issued Notice 725 informing shareholders that, despite AT&T's contention, they must report 39 cents per old share as dividend income on their 1984 tax returns . Notice 725 contains a warning that failure to report this additional dividend could lead to a penalty for underreporting."

Now we get to the latest development. On April 17, the Tax Court of the United States, in Edna Louise Dunn Trust v. Commissioner, ruled against the IRS, determining that no part of the Pacific Telesis stock distributed by AT&T represented a taxable dividend.

As a result, the IRS is developing procedures for AT&T shareholders who reported the dividend income to claim refunds of the tax paid on that 39 cents a share. The agency hopes to issue details of the procedure shortly -- perhaps as soon as the end of June.

The plan is to send letters explaining the procedure to the news media and to all who were sent Notice 725, which advised them to report the dividend as taxable income. Meanwhile, taxpayers are asked not to file amended tax returns or claims for refunds.

Q: I worked for a company that had a retirement plan to which I contributed from my after-tax pay. I left the company, and it sent me a check for all my contributions because I wasn't there long enough to vest. Can this money be rolled over into my IRA on top of the regular $2,000 contribution?

A: No. Voluntary contributions to the company plan from funds on which you had already paid income tax may not be rolled over to an IRA. Rollovers do not count against the regular annual IRA ceiling; but they are limited to employer contributions or your own tax-deferred contributions (such as to a Keogh or simplified employe pension plan).

Q: Since 1980, I have owned shares in a public utility and have reinvested the dividends in additional shares, taking advantage of the annual tax deferral (now expired). I would like to transfer all the shares to my sister as a gift. Do I have any tax responsibility on the gain on these shares? What is the cost for tax purposes when she decides to sell?

A: You have no income-tax responsibility on the gift; but you may be responsible for filing a gift-tax return if the total value of all gifts to her in a single year exceeds $10,000. Assuming that the market value on the date of the gift exceeds your cost basis on the original shares, your basis becomes her basis for figuring gain or loss on a future sale.

I specify "your cost basis on the original shares" because your basis for the reinvested shares, on which income tax liability had been deferred, is zero. Thus, your basis for the total package is simply the cost (including broker commissions) of the original shares.