If the Federal National Mortgage Association, once a part of the federal government, has failed to evolve as superstar among public companies, it is largely because of investor fears about government intervention, one Wall Street analyst told his fellow Fannie Mae stockholders recently. Those fears appear to be on the verge of coming true.

Ever since Uncle Sam "spun off" FNMA to the free enterprise system, there have been questions about the corporation's proper role. Basically, its task of aiding the home mortgage market through periods of tight and easy money was not changed in the conversion from a government bureaucracy to New York Stock Exchange-listed corporation.

However, Fannie Mae has faced a schizophrenic challenge of adding to its profits - and luring private investors - while pumping money into the housing markets. At times, aiding the mortgage market also means a decline in profits.

Thus, as New York analyst Elliot Schneider told his fellow stockholders at Fannie Mae's recent annual meeting, there always has been a suspicion by some investors that the federal government might step in at any moment and attempt to play a larger role in the company's affairs.

The Development of Housing and Urban Development has a vague responsibility for regulating Fannie Mae but has done little of substance in the past to alter the decisions of management. In addition, the 15-member board always has included five persons named by the President, to emphasize the public accountability of Fannie Mae. But there has been no evidence that these directors have forced FNMA to follow courses of action that were not planned otherwise.

Now, changes are afoot and Fannie Mae is about the feel the strong hand of government. With the Democrats back in control of the Executive branch after eight years - a period in which FNMA conducted its initial years as a private firm under Republican administrations - there is evidence that FNMA will be forced to bow a bit.

In two days of hearings before the Senate Banking Committee next week, Fannie Mae will face criticism of its past practices and the company's officers will speak out against legislation proposed by committee chairman William Proxmire (D-Wis.) and Sen. Alan Cranston (D-Calif.).

The Proxmire-Cranston bill would expand the Fannie Mae board by four directors - who would be Presidentially-appointed - giving private stockholders a slim 10 to 9 majority. In addition, the proposed legislation would open up Fannie Mae documents to the public under the Freedom of Information Act.

Officers of Fannie Mae have reacted with panic to the proposal, charging that it would violate the Constitution by depriving investors of their original proportion of directors on the board. They maintain that it would make FNMA the only private firm in the nation forced to disclose documents that would breach confidentiality. The company has hired the Edward Bennett Williams law firm, Williams and Connolly, "to assist us in convincing the Congress of the injustice of the proposed legislation and to contest it in the courts if it becomes law," executive vice president Lester P. Condon said.

Although a battle is about to be waged over the surfacing of political interest in FNMA, the corporation would not be changed dramatically even if the proposed legislation becomes law and is upheld by the courts.

As a recent report on FNMA by the investment firm of Loeb Rhoades & Co., noted: "Politics . . . is always important in assessing the investment merits of FNMA, although currently FNMA's appeal as an investment appears to outweigh political factors. One reason is because of the remarkable stability its shares have recently shown . . . . We are impressed with FNMA's steady earnings progress and its rising dividend trend."

Schneider, who has followed Fannie Mae since its inception as a private firm, sees the Proxmire-Cranston legislation, however, as "insulting and dangerous." The main threat of the proposal is the extent by which it reduces investors' faith in FNMA, he added.

"Fannie Mae has succeeded and grown because it served the public well. (It) could not work if it was not profitable, it couldn't borrow if it couldn't attract investors . . . . This company lives on credit," he asserted. Noting that public debt offerings account for some 96 per cent of FNMA's capital, he argued that "measures that changes the rules of the game" could mean that the investors won't buy FNMA issues with low yields as they have in the past.

If confidence is weakened, FNMA borrowings will cost more and the public interest will suffer, he added. "Investors do not buy uncertainties at 100 cents on the dollar."

Schneider expressed particular concern that the Proxmire-Cranston legislation implies there is "something wrong with Fannie Mae." If there is any such evidence, members of Congress should act to seek removal of any FNMA officers for "good cause."

Otherwise, people on the Hill should shut up, he implied. Moreover, he attacked the record of Congress on housing in recent years and said the Hill's record of aiding the nation's housing needs was "not anywhere near so good" as that of FNMA. Specifically, he said Congress watched passively as the Nixon-Ford administrations put a hold on housing programs.

A member of Proxmire's staff, Jo Ann Barefoot, said these fears and the reaction of FNMA management represent an over-reaction to the proposed legislation. "We don't want to change the nature (of FNMA) as a profit making corporation. The charter clearly says it must make a reasonable profit. We don't want it to lose money or hurt stockholders," she said.

But FNMA chairman Oakley Hunter, in a recent letter to stockholders, urged them to speak out on the legislation. A formal FNMA statement said:

"FNMA is unique in that is has a corporate charter granted by the Congress . . . . This charter represents a solemn bond between the Congress of the U.S. and the shareholders of FNMA. Shareholders purchased their interest in FNMA with the expectation that they would control two-thirds of the membership of the board of directors. They also expected that the activities of FNMA would be guided by business judgment and not by political considerations."

Some members of Congress believe, however, that FNMA has not kept is "solemn bond" to serve the nation's housing needs as its primary goal.