It was front-page news when UAL Inc., parent of United Airlines, announced earlier this month that it planned to convert to corporate use an estimated $962 million in assets from its employes' pension fund.

UAL's move attracted attention because the company was already in the news: Its pilots were on strike and most of the airline's flights were grounded. But what UAL did, while controversial, was not unusual. UAL only was joining a long and growing list of major corporations that are taking back, or "recapturing," money they have put into employe pension funds.

Since Jan. 1, 1980, 729 corporations either have terminated pension plans or have applied for permission to do so, to recover $6.7 billion in assets that exceeded their accumulated pension liabilities, according to the federally chartered Pension Benefit Guaranty Corp. These figures do not include UAL.

Among the corporations that have tapped their pension assets or are about to do so are Firestone Tire & Rubber Co., Great Atlantic & Pacific Tea Co., Reynolds Metals Inc., Amax Inc., Timken Co., Celanese Inc., Harper & Row Publishers Inc. and Occidental Petroleum Corp. Occidental recouped $375 million from the pension assets of Cities Service Co. after acquiring the company, according to material compiled by the House Select Committee on Aging.

J. P. Stevens & Co., the nation's second-largest publicly held textile company, announced Thursday that it had recovered $112 million in assets from a salaried employes' pension fund and would use the money to reduce debt or finance acquisitions.

Pension asset recapture has been the subject of intense discussion within the Reagan administration and between the administration and Congress. Even before the UAL announcement, Rep. Edward Roybal (D-Calif.), chairman of the Committee on Aging, had introduced legislation that would sharply restrict the ability of corporations to tap pension assets.

The issue involves what are known as defined-benefit pension plans -- pensions in which an employer is committed to pay a specified level of benefits to vested employes and retirees. If interest rates on the invested funds rise, inflation declines, investment income exceeds projections or unexpected numbers of workers leave the company, it is possible for the pension funds assets to exceed what is required to cover the specified benefits. (Defined contribution plans, in which an employer makes specified contributions to a fund but the level of benefits is determined by what those investments will buy, are not affected, because by definition they never are overfunded.)

Like so many issues in Washington, pension asset recapture resembles an old movie in which the same incident is recalled by different participants -- whose accounts, of course, differ greatly from each other. The longer the film goes on, the more murky the truth becomes. Pension asset recovery involves complex questions of taxation, collective bargaining, fairness, social policy and economics that so far have defied regulatory and congressional efforts to resolve them.

The corporate view -- generally supported by the administration -- is that establishment of a pension is a voluntary act by management and it's the company's money. In this view, so long as all obligations are paid off, no one loses and the funds can be put to good use. UAL, for example, said it would use the $962 million to finance corporate expansion, such as its purchase of 25 Boeing 737s from Frontier Airlines and its proposed acquisition of Pan American World Airways' Pacific routes.

In addition, corporations regard overfunded pensions as an invitation to unfriendly takeovers: The excess assets become an enticing target for any potential acquirer. The German owners of A&P, for example, recaptured five times as much from the pension fund as they paid for the company, according to Sen. Howard Metzenbaum (D-Ohio), who has been pressing the administration for a moratorium on such transactions.

Critics see pension recapture as little more than a corporate rip-off of workers and retirees -- even though all benefits accrued up to the moment the assets are withdrawn must be paid.

At a hearing before Roybal's committee two days after UAL's announcement, Rep. Claude Pepper (D-Fla.) said there is "no more contemptible an act than the conspiracy of those entrusted with the management of pension funds to convert the assets for their own interest."

The American Association of Retired Persons, one of the nation's most potent lobbies, argued in a statement to Roybal's committee that asset reversion actually cheats beneficiaries because "pension benefits are no longer a reward, but a right." Many workers accept lower current wages in exchange for higher retirement later, the AARP said. "Since plan assets are actually employe earnings, public policy should dictate that the raiding of excess pension funds for the sole benefit of the employer at the expense of participants and beneficiaries is unfair and contrary to the very purpose of pension plan funding."

Even if all vested beneficiaries of a pension plan receive their full accrued benefits, the AARP and other critics argue that they lose out because they can't bargain for benefit increases later on, they are left without insulation against inflation and they lose the protection of the pension insurance provided by the Pension Benefit Guaranty Corp.

The administration's view was outlined in a March 25 letter to Roybal from Ronald A. Pearlman, assistant Treasury secretary for tax policy. "This administration is committed to assuring that qualified defined-benefit plans established by employers actually deliver the promised retirement benefits to employes and their beneficiaries . . . . The continued viability of this pension system is one of the administration's highest priorities," Pearlman wrote.

But he noted that "the private pension system is a voluntary system" and that the law permits an employer to terminate a pension plan if all accrued benefits are paid.

Existing law prohibits an employer from withdrawing assets from a pension plan. But it permits an employer to terminate a pension plan and keep what assets remain after covering existing obligations, usually through the purchase of annuities from an insurance company. Many employers who have done this have created new plans, in which assets and liabilities start from scratch, to cover their employes and future retirees, but experts say they are not obliged to do so unless employes are covered by a union contract that specifies maintenance of a pension plan.

Critics say this system allows corporations to build pools of tax-deferred assets and use the money for purposes not intended by the law. But even many of these critics acknowledge that restrictions on the rights of corporations to tap these assets may influence many of them not to establish pension plans in the first place.

This argument dissuaded Treasury and the IRS from prohibiting "reestablishment and spinoff" transactions that are not true terminations, Perlman told Roybal. Instead, the administration last year published what it called "guidelines" specifying that all accrued benefits be covered by annuity contracts and requiring IRS approval of the transactions.

But these guidelines are being challenged in court, and Roybal has introduced legislation that would go much further. His bill would impose a "business necessity" test. Employers who could show they were terminating a pension plan as a "business necessity," as in a bankruptcy, would be permitted to recapture excess pension assets but would be required to pay a 10 percent excise tax. Absent a "business necessity," the excess assets would have to be distributed to workers and retirees -- a provision that aides to Roybal acknowledge would be tantamount to a prohibition on such transactions.

Metzenbaum said a consultant's study of 200 defined-benefit pension plans found that "83 percent were 'overfunded,' making them prime candidates for termination." But it is not certain that many more companies will jump on this bandwagon -- or even that a bandwagon is rolling.

David M. Walker, acting executive director of the Pension Benefit Guaranty Board, told Roybal's committee that "the plans from which large reversions have been recovered represent less than 1 percent of total plans and only 2.6 percent of all defined-benefit pension plan participants. These statistics show that, in the light of the overall pension universe, reversions are the exception rather than the rule."

The reason for that may be that many companies do not find pension termination economically attractive, according to Harold Dankner, a partner and pension specialist in the accounting firm of Coopers and Lybrand. Most companies that have consulted him about it, he said, "have rejected the idea," he said.