If anything like the president's tax-reform proposal makes it into law, it will create an entirely new climate for saving and investing. Old-fashioned favorites will come back into style; new-fangled tax ploys will wither away. Some planning ideas:
* Your savings. The president's tax plan might quell the urge to borrow, because of the limits on interest deductions. If borrowing slides, interest rates could come down. On that assumption, it would make sense to lock up longer-term certificates of deposit at today's interest rates, and to invest in mutual funds that buy bonds. If interest rates decline, the value of bond-fund shares bought today will rise.
Long-term municipal bonds, incidentally, remain attractive for investors who expect to be in the top, 35 percent bracket.
* Your stock and stock-mutual-fund investments. If interest rates settle at a lower level, the stock market will be worth relatively more than it is today. Companies getting a tax cut under the Reagan plan might be worth a second look: among them, some retailers, food and cosmetics companies, and trucking, tobacco, drug and publishing firms. (Industries likely to pay a higher tax include autos, steel, machine tools, airlines, mining, oil, utilities, construction, insurance and banking.)
Tax cuts alone will not make a stock go up if, at the same time, earnings are going down. But when business improves, stocks and stock-owning mutual funds will have an extra edge: Under the Reagan plan, taxpayers in the top, 35 percent bracket would pay a capital-gains tax of only 17.5 percent, down from 20 percent today. In the 25 percent bracket, you'd pay 12.5 percent on your capital gains, and in the 15 percent bracket, 7.5 percent.
* Your insurance and tax-deferred annuities. When you buy cash-value life insurance today, the earnings on that cash build up in your policy tax-deferred. The same is true of the widely sold tax-deferred annuities.
The Reagan plan would tax that cash annually, as it builds up -- a proposal that the insurance industry has vowed to defeat. Fans of these investments might want to buy now, just in case the insurance industry loses its case. If this portion of the tax plan passes, the tax deferral on cash-value life insurance and tax-deferred annuities (except pension annuities) would be lost, on policies sold after the proposal is approved in congressional committee.
* Your retirement savings. Today, two-earner couples can save up to $4,000 in Individual Retirement Accounts, while one-income couples are limited to $2,250. The Reagan plan evens couples out at $4,000.
Another change would affect the thousands of employes who save money in the popular tax-deferred 401(k) plans, offered by a growing number of companies. At present, high-earning employes can put up to $30,000 in the plan, while their lower-earning colleagues can save much less. The Reagan plan would impose a new ceiling on your 401(k) contributions of $8,000 minus your IRA contribution. Anyone able to save a higher amount might try to do so this year, just in case it's your last chance.
In one respect, 401(k)s have become less attractive as a savings vehicle.
Currently, you can withdraw money from the plan without penalty in case of hardship, which some companies define loosely to include expenses like college tuition. But under the Reagan plan, you couldn't normally withdraw before age 59 1/2, except in cases of death or disability. So if you already have entered a 401(k) with the intention of withdrawing funds for college or other allowed expenses, ask your company if you can get the money out before the end of the year. After that, you might be stuck. For long-term retirement savings, however, 401(k) plans remain attractive.
* Your investment partnerships. Deals set up to earn steady income for investments will survive the holocaust. But many of the macho tax-shelter partnerships sold by Wall Street will lose their hair. Shelter salesmen are already out in force, urging you to buy last-chance deals. The sooner you do so, the better. As the months, pass the good deals will all be gone -- leaving a market full of stinkers.
* Your lost deductions. Among the write-offs to bite the dust are the working-couple deduction, the child-care credit (it's replaced with a lower-valued deduction), state and local taxes, the extra personal exemption for the blind and the elderly (replaced with a lower-valued tax credit) and the small charitable deduction for taxpayers who take the standard deduction. But for most Americans, the loss of these deductions is more than atoned for by higher personal exemptions, higher standard deductions and lower tax rates.