FOR those wringing their hands about the low savings rate in the United States, economist Arnold Moskowitz has some solace. It is a temporary phenomenon arising mostly from the age of the baby-boom generation, says the senior vice-president of Dean Witter. The members of that demographic group have been big spenders. They have been at the age - 20 to 34 years - when they are buying houses, cars, and clothes, raising families, going into debt in grand style.
In a few years, however, baby-boomers will be reaching the age when people become savers.
``Although it may not seem possible, yuppies do grow up,'' Dr. Moskowitz says.
In the postwar period, savers (aged 45 to 54) peaked at 22 percent of the adult population in 1966. The ratio of spenders (aged 20 to 34) to savers was 1.66.
Then as the baby-boom generation left school, the number of spenders rose dramatically, rising from 41 million to 62 million between 1969 and 1983, overwhelming the savers. By 1986, savers accounted for only 16 percent of the population, the ratio of spenders to savers was 2.8, and the personal-savings rate had plunged to its lowest postwar level, 3.5 percent.
Moskowitz continues, however, that by the year 2000 the spenders will have declined from 63.6 million today to 53.5 million. Savers will have reached 23.5 percent of the adult population. The ratio of spenders to savers will have declined to 1.4, even less than in 1966.
The impact of such demographic changes takes time. But Moskowitz guesses that the nation is now moving along the bottom of the personal-savings rate pattern and that a noticeable improvement in savings will have occurred by 1992.
Current fears about the low savings rate damaging business investment and otherwise harming the economy are ``overdone and overdrawn,'' he says.
Today a common lament is that the US has become the world's biggest debtor nation. By sometime in the next decade, the US will once more be ranked as a major net creditor nation, Moskowitz predicts. American financial institutions, struggling to find good investments for rapidly growing savings, will again be placing money in third-world nations.
With the burgeoning of a surplus in the social security system (about $45 billion a year now), the federal budget deficit would disappear. Indeed, under current law, accumulated social security reserves could reach $3.4 trillion by 2015.
Comments Morgan Guaranty Trust Company: ``With careful husbanding, social security surpluses present an unequaled opportunity to boost the US net savings and investment rates, perhaps to as much as 8 percent of GNP [gross national output, the total output of goods and services] - a level not achieved since the mid-1960s but necessary to provide for the future prosperity of both retirees and the working population.''
Moskowitz figures the number of baby-boomers reaching savings age will make it politically impossible for Congress to use up all the burgeoning social security surpluses in additional benefits. Boomers' clout will also make the Federal Reserve System exercise monetary restraint to protect their savings.
The arrival of a savings era also promises a continuation of the bull market in stocks and bonds, says Moskowitz.
So maybe the baby-boom generation isn't all bad news of crowded schools and extreme competition for promotions up the corporate ladder.