If U.S. exporting companies have a friend in Washington, it has to be John L. Moore Jr., who is chairman of the Export-Import Bank, that grey, unobtrusive pile located across Lafayette Park from the White House.

Under Moore, a former Atlanta attorney appointed to his post by President Carter in May 1977, the Ex-Im Bank has aggressively financed billions of dollars a year in U.S. exports by lending funds to foreign buyers at rates ranging between 7 3/8 percent and 8 3/4 percent. In fact, the Ex-Im Bank is nothing less than a taxpayer-financed subsidy program with the ostensibly worthy mission of improving America's balance-of-payments position.

Ex-Im Bank's borrowers are foreign entities that must use incredibly low-interest rate loans to buy American-manufactured products. So when the top executives of America's biggest companies got personal letters from Moore late last year, they read them with care. But to many of the businessmen, the message between the lines was troubling. In those letters, dated nov. 5, 1979, Moore was asking the corporate executives whose exports his bank had subsidized so generously to provide the bank with a subsidy from their own corporate coffers.

In the letter, obtained from the bank through a Freedom of Information request, Moore explained that the Ex-Im Bank had been unable to raise enough money to administer the program, announced earlier, to get minority-owned banks into the export-financing business. Moore wrote that he figured the program would cost $175,000 to operate for 12 months, but "due to Ex-Im Bank's budget limitations, the maximum amount which we are able to provide for this important project is $25,000."

Moore then said he was asking "each of you to consider participating in the $150,000 balance." He said the Ex-Im Bank would be "custodian" of the funds, which would be used pay expenses such as the fees of a private consulting firm called Industry Consultants Inc. The Washington-based firm, founded in July 1978, is helping the Ex-Im Bank staffers administer the program.

Back in January 1979, when the program first was announced, Moore initially had sent a letter to the heads of some 40 major corporations simply requesting that the companies direct business to minority banks. All the companies readily agreed to that request from Moore. But to a number of executives -- and to many members of the Ex-Im Bank staff -- Moore's later request that the companies help finance the program was fraught with obvious conflicts.

Most obvious, of course, was that Moore wanted contributions from companies that regularly come to him seeking help in export financing. "It just seemed that he was putting on arm on us," said one export executive. And while a major exporter hardly could complain about putting up a few thousand dollars for such an apparently worthwhile program when it benefitted from hundreds of millions of dollars of financing extended its foreign customers each year by the Ex-Im Bank, there was a troubling principal involved here.

Even so, all but a few companies contributed $3,000 or $10,000 each towards the program. The bank would not release the list of contributors, but a knowledgeable industry source said they included Boeing with $10,000, Lockheed $6,000, McDonnell Douglas $5,000 and United Technologies $7,500. lWith support for Moore's minoritybanking program coming from aerospace companies, it is noteworthy that under Moore 52 percent of $3.7 billion in export credits extended by the bank so far in fiscal 1980 has gone to finance U.S. aircraft sales.

Although many of the top executives were reliably reported to have been troubled by the implications of Moore's pitch, only one company is known to have refused to contribute as a matter of principle. According to William L. Neely, treasurer of Rockwell International Corp. in Pittsburgh, his company "was quite willing to lend a hand as (the Ex-Im Bank) had envisioned (the minority banking program) originally." But, added Neely without elaboration, "When it came down to supporting Ex-Im Bank's budget, that's where we had to draw the line."

While Moore allows that his program does give the appearance of putting the arm on corporations, he said "we made it clear that it was voluntary. We were asking for a nickel of their assets for a very worthy program."

Others say that Moore also may have been mindful that the program might have paid political dividends for Jimmy Carter among blacks and other minorities. But when Moore belatedly relized that the Ex-Im charter wouldn't allow him to dip into the bank's already strained budget for the pet project, he turned to the corporations for a bailout.

Moore, it seems, should have been sensitive to any ethical problems in the minority banking program. After all, during the days just before Carter was sworn into office, Moore wrote the set of stiff ethical guidelines for the new administration. As the administration's ethical watchdog, Moore reviewed Bert Lance's dealings and apparently concluded that the Georgia banker could be named budget director without fear that his scrapes with bank regulators someday would embarrass the new president.

Since Carter named Moore chairman of the Ex-Im Bank, criticism has ranged from those who call him surprisingly naieve to others who see him sufering a terminal case of Potomac fever. Moore is accused of being a poor administrator who has let the bank drift without a captain as he travels the world.A number of observers inside and outside of the bank say morale has plummeted, and careerists accuse Moore of politicizing the bank through his appointments and in other ways.

Recently, the normally invisible Ex-Im Bank burst into public view when it agreed to lend some $201 million to 8 percent annual interest for 10 years to an airline Down Under half-owned by Australian financier Rupert Murdoch. The loan, part of a larger package, was to enable Murdoch and his business partner to buy five Boeing 767 widebodied jets to match the seating capacity of four wide-bodied planes purchased by their Australian domestic competitor from Airbus Industries, a European aircraft manufacturing combine.

It wasn't the size of the loan that triggered the controversy: the Ex-Im Bank recently loaned nearly $1 billion at about the same interest rate on another deal. Rather it was the distinct scent of politics -- suggested in news stories describing the loan deal.

As the stories noted, in the midst of a meeting about the loan with Ex-Im Bank officials, Murdoch took a break to have lunch with President Carter at the White House. Two days after the luncheon, on Feb. 21, Murdoch's New York Post became the first big-city daily to endorse Carter's re-election. Seven days later, after Moor pressed the staff to complete research in a tremendous rush to meet a Murdoch-imposed deadline, the Ex-Im Bank board approved a $201 million loan to Murdoch's Ansett Airlines.

Last week, two key members of the Senate Banking Committee -- Chairman William Proxmire (D-Wisc.) and Adlai Stevenson (D-Ill.), chairman of the subcommittee on international finance -- sent a letter to the bank demanding a detailed explanation of the loan. They set April 3 as the deadline for meeting their extensive demands, including tape recordings of board meetings a which the loan was discussed.

Adding a further patina of politics to the Murdoch loan is that Moore's former Atlanta law partner, Philip Alston, a long-time Carter supporter, is ambassador to Australia. While Alston and Moore did exchange phone calls during the ansett loan negotiations Moore says no political pressure was brought by Alston or anyone else. What's more, Moore says, the low interest rate of 8 percent on the loan used in the purchase of the Boeing 767s was extended to Ansett to match a rate offered by Airbus of 7.95 percent.

Puffing on his pipe during an interview in his large office that overlooks Lafayette Square, the White House and beyond, Moore said that Murdoch didn't even mention that he was having lunch with the president when he broke off negotiations that day.

When Moore took office at the Ex-Im Bank, he lowered the lending rate spread charged by the bank from a range of 8 1/2 percent to 9 1/2 percent to a range of 7 3/8 percent to 8 3/4 percent. And even with interest rates soaring all around the bank -- and with the Ex-Im Bank itself paying 13 percent for money it lends at 8 percent -- Moore sees no need for higher rates so long as foreign governments are offering comparably low rates to subsidize their exports.

But a former high bank official criticizes Moore for not carefully analyzing the bank's lending policies. "No respectable economist would defend what he's doing," says this person, echoing a sentiment voiced by others interviewed for this article. "John Moore isn't managing. He's got the ability, but he's having a grand time flying around the world."

A review of Moore's travel vouchers shows that he was away from the bank more than 200 days in 1979, a wanderlust that began as soon as he took office and shows no sign of abating. Moore says the travel was to drum up business lost by his predecessor, Stephen DuBrul, a New York investment banker who made only one foreign trip in 16 months and was tight-fisted with bank funds. Under Moore, there has been a 600 percent increase in direct credits to foreign buyers and U.S. products.

Moore's extensive travels, mostly in first class compartments, and similar wanderings by some other board members have sopped up much of the funds budgeted for travel by the bank. This leaves precious little money to finance working trips by the bank's career professionals.

Most of Moore's appointments within the bank have come under sharp criticism, but none more than that of Mat Schaffer. Schaffer, 30, is another ardent traveler, who recently boasted he has visited a slew of countries during his brief couple of years in the bank. Like Moore, he is a Georgian and a former Rhodes Scholar at Oxford University.

The trouble is, Schaffer's doctorate was in anthropology. Without any apparent experience in business or banking, he has risen meteorically to senior vice president of the Ex-Im Bank, making him the bank's third ranking official, to the dismay of some careerists. Moore dismisses critics of Schaffer within the bank by saying, "He's not in the career mode." He maintains that Schaffer "has performed well."

As for the future, Moore says he wants to stay on as chairman of the bank if Jimmy Carter is re-elected. It's a marvelous place to work, he says.