Despite recent tax changes and rulings that restrict certain traditional avenues to tax shelters, finding a shelter still is not difficult. But sheIter with liquidity is increasingly harder to come by. Tax-advantaged partnerships, for example, are apt to tie up investors' funds for years with no market for their interests. Annuities have now been complicated by penalty taxes on certain withdrawals. And even the recent expansion of IRA and Keogh tax-deductible contributions doesn't really help relieve illiquidity: There is a stiff charge if funds are withdrawn before you reach age 59 1/2.

A tax-deferment setup that only lately is being explored, even though the opportunity has been around for decades, is an open-ended fund called a tax-managed trust, a type of registered investment company of which there are but a handful in the country. It is called "tax-managed" because, unlike the typical mutual fund, gains aren't passed through to investors, and hence there isn't any tax liability for them. And if operated nimbly, theoretically neither a tax-managed trust nor its shareholders ever has to pay a federal tax, no matter how substantial the papergains.

As with an IRA, Keogh, or tax-qualified pension plan, a shareholder of a tax-managed trust is able to reinvest and compound income without incurring a tax liability. But what is advantageous about the ceilingless (you can put in as much as you want, but, of course, the contribution isn't deductible) tax-managed trust is that, if the sale is executed properly, the investor can liquidate all or part of his or her position, subject only to long-term capital gains treatment on the profit. (When an IRA is liquidated, the entire amount, however accrued, is considered ordinary income. And if the IRA happens to have lost money -- a possibility in a self-managed account -- the loss cannot be taken as a tax deduction.) Further, starting in July, when withholding or "advance" taxation on interest and dividends goes into effect, an ancillary advantage of the tax-managed trust over dividendor interest-paying vehicles will be that no withholding is required by the IRS. An investor's money will be at work 100% of the time, rather than partially lining the Treasury's pockets.

The enabling legislation of this apparatus is Sec. 243 (a)(1) of the 1954 Internal Revenue Code, which allows a U.S. corporation to deduct from taxable income 85% of the dividends received from another domestic corporation. The typical mutual fund elects not to be taxed as a corporation and passes through more than 90% of income directly to shareholders, who are obliged to report such income on an individual basis in the year it is received. But a tax-managed trust purposely elects to be taxed as a corporation. It reinvests all income and distributes nothing to investors. Since the other 15% of dividends received is deducted in business operations, the trust essentially pays no taxesIf market conditions warrant, however, from tirne to time it may also take capital gains on sales of its holdings at the corporate rate.

The rules allow some nifty tax-management exercises. For example, the trust may leverage itself, thus putting more capital to work, and deduct the interest costs against capital gains. It can also sell covered call options. To offset option revenue, the fund manager can execute an ingenious maneuver that brings in dividend income while purposely losing capital. He buys stock just before it goes exdividend and sells the stock immediately afterward at the automatic loss caused by the dividend's being subtracted from the price to the stock on the "ex" day.

Because it focuses exclusively on quality, high-dividend payers, much of a tax-managed trust's portfolio is in conservative common and preferred stock issues such as utilities. It fares particularly well when interest rates drop, as was the case in the latter half of 1982. Then its interest-sensitive holdings increase in price, adding considerably more to net asset value than dividend reinvestment alone. It has been estimated that a decline of two points in long-term interest could boost diversified portfolio as much as 25%.

A shareholder in a tax-managed trust can create a systematic program that will provide a steady monthly income with only capital gains tax exposure. Let's say the shareholder buys $100,000 worth of shares (as little as $250 worth can be committed) and wishes to take out $10,000 annually. He arranges through the fund to redeem enough shares each month to produce $833-34. For tax purposes, the gain or loss is calculated on the basis of the shares and the sale price, as in any stock transaction. And if the fund is operating at a gain in net asset value of more than 10% -- a cinch these days -- his nest egg replenishes itself.

The actual results in one case show that a $100,000 investment (less $3,481 initial sales charge) made in a certain fund in November 1978 would have been worth $94,659 on October 31, 1982. During that period, however, $39,167 would have been withdrawn on the monthly basis, resulting in a taxable gain of $3,234, on which the maximum tax would have been only about $646. All told, the fund's net asset value gained 1% in 1979, 11.1% in 1980, 17.5% in 1981, and through October 31, 1982, was up a highly respectable 18.6%.

These are not especially dramatic figures, but they can be. An individual investing solely in tax-free municipal bonds might have done even better, just as an individual investing in stocks might best a mutual fund. But he would not have been able to tap the higher yields of utilities and other equity sources, nor would he have been able to convert such yields into long-term capital gainsHe also would not have gained the extra earning power of option sales and leverage -- bonuses that clearly were bearing fruit in 1982's market climate. Tax-managed trusts' late-blossoming popularity (two large funds were recently founded) suggest that investors are now discovering that an astute fund manager is able to make tax-managed trust holdings quite interesting.