Federal investigators probing the collapse of O.P.M. Leasing Services Inc., the huge New York computer-leasing firm, reportedly have found documents suggesting that the well-known philanthropy by the company's co-owners may have been the result of more than generosity.

According to a source close to the probe, investigators have found wire transfers of funds from a number of charities to accounts established in the name of one of O.P.M.'s co-owners. The investigators believe that the funds represent portions of some contributions that were being kicked back to the giver.

Over the years, O.P.M. founders Mordecai Weissman, 33, and Myron Goodman, 34, have given huge amounts of their wealth to charities, many of them Jewish organizations in this country and in Israel. Goodman had made generous contributions to Yeshiva University in New York City where he was the youngest trustee in the institution's history until he resigned recently.

Weissman and Goodman's rabbi, Gilbert Klaperman of Congregation Beth Sholom in Lawrence, N.Y., where the two men -- boyhood friends from Brooklyn and married to sisters -- live on neighboring estates, said, "I know myself of $1 million or more in contributions [to various charities] by the two men in the past year."

According to two separate sources, investigators have found documents indicating that O.P.M. deposited funds in bank accounts opened in Goodman's name. The sources say that the documents characterized the transfers of funds as loans. The funds then were contributed to charities, but transfers of funds are loans. The funds then were contributed to charities, but the documentation indicates that some of the money allegedly was returned.

The sources say that although the accounts were in Goodman's name, Weissman was aware of their existence.

The sources would not disclose the names of the charities suspected of returning funds to Goodman, but one said that investigators believe "huge sums" of money are involved in the alleged kickback scheme.

Dr. Sheldon School, a vice president of Yeshiva, said yesterday that he is certain that the university was not involved in the alleged scheme. "I can only tell you with certainty that we would not be part of such a thing," he said in a telephone interview.

Rabbi Klaperman, who said the two men were "among the most outstanding philanthropists in the country," said he did not believe the allegation of kickbacks.

A federal grand jury in Manhattan has been probing fraud allegations against O.P.M., Weissman and Goodman. O.P.M. has file for bankruptcy reorganization, and the two men have filed for personal bankruptcy.

The grand jury criminal investigation grows out of allegations made in February by Rockwell International Corp., the giant Pittsburgh conglomerate, that banks, insurance companies and others had lent money to O.P.M. to finance computers supposedly leased to the company, computers that Rockwell said it had never ordered or received.

Last month, about a dozen of the lenders filed suite against O.P.M. and its two founders, alleging that O.P.M. had borrowed millions of dollars based on phoney computer leases and sales contracts.

Sources say that investigators have uncovered about $100 million in fraudulent loans purportedly used to finance computers going to Rockwell. Another $100 million or so of allegedly fraudulent loans reportedly were made to finance computers leased to other O.P.M. customers. The names of the other customers could not be learned.

O.P.M., which stands for "other people's money," was co-owned by Weissman and Goodman. The company leased hundreds of millions of dollars worth of IBM computers to some of the country's biggest corporations and, in its 10-year existence, became the No. 2 computer-leasing firm in the country.

O.P.M. and other leasing companies act as middlemen between financiers and the users of the equipment. Normally O.P.M. would buy a computer from IBM with financing provided by banks, insurance companies, pension funds or other sources. Once the lease expired in four years or more, O.P.M. would find a secondary market for the used machines.

But like its biggest competitor, Itel Corp., which is also in bankruptcy, O.P.M. had allowed customers to cancel their leases early without penalties as a sales incentive. This policy brought on O.P.M.'s -- and Itel's -- downfall when in 1977 IBM introduced a new line of computers, which were smaller, faster and lower-priced than anything then on the market. O.P.M.'s customers canceled their leases in droves to switch to the new machines.

Sources believe that the alleged fraudulent activity by O.P.M. was part of a desperate attempt to survive the IMB bombshell.