The Supreme Court yesterday agreed to decide whether federal laws protecting buyers of securities against fraud apply to union pension funds paid for by employers and compulsory for employes.

In an unprecedented ruling in August, the 7th U.S. Circuit Court of Appeals held that the antifraud provisions of the Securities and Exchange Acts of 1933 and 1934 protected John B. Daniel, a Chicago truck driver who was a member of Teamsters Local 705 for 22 1/2 years.

During 12 of those years, employers covered by the local's Pension Trust fund made payments to it in Daniel's behalf. He expected to get $400 a month in retirement benefits.

Because of cataracts, Daniel, now 69, was forced to retire in November 1973. A month later, the fund told him he wouldn't get a cent, and the money paid in for him, and the interest it had earned, all would be forfeited.

The reason: without knowing it, Daniel had broken a rule of the fund for 29 years' continuous service, jointly administered employer-union Te interruption was in 1960-61, when an employer who fell on hard times laid Daniel off for four months.

The appellate court ruling has aroused concern across the broad sector of the economy involved with private pension plans. As of 1973, the plans covered 30 million workers; as of 1977, their assets had a book value of $217 billion.

The plans are the largest single source of private investment capital. To exempt them from the antifraud provisions would be to leave capital markets "significantly" unpoliced, Judge Walter J. Cummings wrote in the opinion for the court.

He said the provisions applied to Daniel because he was an "investor" whose interest in the fund was a "security" acquired in a "sale." But Judge Philip W. Tone, while voting with Cummings, expressed "certain doubts" about the definitions.

The Supreme Court granted petitions to review the decision filed by the local and the international union.

Numerous friend-of the-court briefs --tional Association of Manufacturers and the AFL-CIO -- don't question that Daniel got a raw deal. But they warn of dire consequences if the justices affirm the decision.

On the other side, the non-profit Gray Panthers group organized to help the elderly, says critics of the ruling operate from a "manifestly false" premise; that Congress has been satisfied to make joint pension boards the sole protectors of workers against arbitrary and capricious treatment.

The Securities and Exchange Commission had told the appeals court that the antifraud provisions apply to misrepresentation and nondisclosure of material facts such as experienced by Daniel, who founded his faith in pension benefits in union booklets and letters. But the Labor Department disagreed, saying that Congress especially had enacted the Employment Retirement Income Security Act (ERISA) of 1974 to deal with pension abuses.

The ruling leaves "considerable uncertainty as to possible liability" of many pension plans for past as well as future conduct, said Solicitor General Wade H. McCree.