The National Bank of Georgia sold off $1.5 million worth of its troubled Carter Warehouse loan in late 1975 to three small south Georgia banks. About eight months later, according to informed sources, the Atlanta bank was forced to use its own funds to pay the small banks $500,000 when Carter Warehouse fell behind in loan payments.

The loan sell-off was not uncovered during a five-month investigation, concluded earlier this year by two NBG outside directors, into the bank's operations under it former chief executive, Bert Lance.This suggests that the bank may have been withholding information from the directors, whose investigation was mandated by the Securities and Exchange Commission.

The outside director who personally checked into the Carter Warehouse loan, Lindsey Hopkins III, said no trace of the $1.5 million loan sell-off - virtually the entire outstanding balance of the loan at the time - had been found in the records he reviewed. Moreover, he said, no bank officer told him of the transaction.

The president of one of the small south Georgia banks, Paul Penn of the Commercial State Bank in Donaldsonville, said all records and coreespondence and the bank's loan liability ledger were subpoenaed on Jan. 30, 1979, by federal agents investigating the warehouse loan.

The buyback of the warehouse loan with $500,000 of the National Bank of Georgia's own assets would appear to be another example of the unusual banking treatment accorded Carter Warehouse at a time when Jimmy Carte was running for president.

Othe new elements in the tangled relationship betwen Carter Warehouse and the NBG, learned by The Washington Post in a series of interviews and review of records, include: An NGB loan officer allowed as much as $1 million worth of peanuts to be sold without reflecting this loss of the bank's collateral on the books for up to two months, according to sources familiar with NGB records.

Department of Agriculture records show that Carter Warehouse was enjoying its most prosperous crop in 1976-1977, the very year it was falling behind in loan payments.

Despite the infusion of $6.5 million in loans from NBG, the Carter Warehouse, now up for sale, has been struggling for its business life since the peak year of 1976-1977. Business is off by more than 60 percent, records show.

Questions about the Carter Warehouse loan grew out of the year-long federal grand jury probe here of the banking affairs of Lance, Former director of the Office of Management and Budget.

Billy Carter testified before the grand jury last October, and he has said he refused to answer certain questions. Billy Carter, who ran the warehouse through the summer of 1977, has told The Washington Post that there was "no wrongdoing" involved in the NBG loan.

Last month, Attorney General Griffin B. Bell appointed New York attorney Paul J. Curran, a former U.S. attorney, the special councel to investigate the NBG loan to Carter Warehouse.

President Carter's 63 percent interest in the warehouse is held in blind trust by Atlanta attorney and close friend Charles Kirbo. Billy Carter has a 15 percent interest, and Jimmy's and Billy's mother, Lillian, has 22 percent.

According to Sumter County Court records, on March 1 Billy gave trustee Kirbo an option to purchase his interest in the warehouse. Kirbo has put the warehouse up for sale.

Hopkins and his fellow outside director, Church Yearley, found, in the course of their SEC-mandated investigation, that "NBG made tentative arrangements to sell participations to other banks."

It now turns out that on Dec. 1, 1975, NBG actually sold a $1.5 million participation to the Commercial State Bank in Donaldsonville. That bank, in turn, sold two $500,000 shares of the loan to the Bank of Terrell in Dawson and the Citizens State Bank in Reynolds.

It is a common practice for banks to sell participations in loans to each other. Banks may do it to avoid exceeding their legal lending limit, to raise funds for other, more profitable loans, to improve the ratio of capital to loans or for a host of other reasons.

It's unclear why NBG, which trumpeted its Carter peanut account in the 1975 annual peanut report, felt compelled to sell the $1.5 million participations to the small banks only five months after it had extended credit to Carter Warehouse. By selling participations in the loan, NBG gave up most of its anticipated profit on the loan. The small banks took the prime rate plus 1 1/2 percent, while NBG retained only 1 percent.

A former vice president of NBG suggests that NBG did it to encourage the small banks to join a statewide system of correspondent banks it was hoping to establish.

But according to other sources, the transaction was fraught with problems and marks by unorthodox banking procedures.

These sources say that as early as 1975 the warhouse was falling behind in loan payments. The loan, they add, was seriously under-collateralized, and the bank failed to document the loan participation sale properly. Those same banking authorities also allegedly raised questions about the adequacy of the collateral backing the $1.5 million deal. State banking authorities declined to comment.

Sources familiar with NBG's records say executives from the three small banks "dunned" the Atlanta bank during 1976 in a series of complaining letters. Reportedly they complained that they were not receiving timely payments from NBG on their participation.

Those same sources say NBG was not paying the small banks because Carter Warehouse had fallen behind in payments to it.

The original agreement between NBG and the three banks reportedly called for full payment of the $1.5 million in March 1976, according to sources. In fact, payments did not even begin until March, Penn said the loan was retired in a series of five payments beginning in March and ending on July 14, 1976.

But other sources say that NBG was forced to pay the three banks the last $500,000 of the $1.5 million loan participation agreement out of its own funds. The bank did this because the warehouse had fallen so far behind in its obligation to the bank, sources said.

The $500,000 NBG was forced to pay the three banks became a part of the $9 million line of credit that was extended to Carter Warehouse on Sept. 23, 1976, according to sources. Thus the second line of credit began with a $500,000 deficit. This was contrary to the loan agreement, which contemplated that the first line of credit would be fully paid off before a second line was extended, sources said.

During the troubled period, the outside director's report said, Lance ordered that the interest rate on the loan be lowered by 2 1/2 percentage points to the prime rate, the rate extended by banks to their best commercial customers. At the same time, NBG also tripled its line of credit to the warehouse to $9 million.

According to the outside directors' report, the reduction in interest "was believed by Lance to be justified by the greater security provided" by the bringing in of an outside factor, Walter Heller and Co., to handle accounts receivable owed to the warehouse. By lowering its interest rate to prime, the Atlanta bank paid for the warehouse's expenses in hiring Heller. Beyond that, NBG also gave up a substantial portion of its profit on the loan.

Several bankers interviewed said they saw no need for hiring a factor. They said that peanut warehouse sell primarily to "blue-chip" accounts, which pay their bills in a timely fashion. A former Heller employe who handled the account confirmed that Heller factored only blue-chip accounts and had no problem collecting from these accounts.

Jimmy Carter met with executives from Heller in Plains in July 1976. The NBG outside directors, in their report, said: "We have been advised the justification for the reduction were spelled out in a letter from Lance to Jimmy Carter, but we have been unable to obtain a copy of this letter."

The letter reportedly was presented to the grand jury here investigating the banking affairs of Lance. White House officials say they have been unable to locate a copy of the letter which has been the subject of repeated requests by reporters.

In another development, it was learned that bank records at times misstated the amount of collateral on hand - peanuts in the ware house - by as much as $1 million.

Under the terms of the loan, no peanuts were to leave the warehouse unless NBG was informed. The warehouse was to forward a duplicate and an original of a form that documented release of a certain amount of peanuts. The warehouse was also supposed to send the bank a check at the same time to reduce the loan balance.

The loan officer was supposed to acknowledge getting the check by certifying the peanut release form and sending it promptly to the Atlanta office of Collateral Contro Corp., the company charged with safeguarding the bank's collateral.

Finally, the loan officer was to remove from the bank's record of collateral the warehouse receipt for the peanuts. This was to be done promptly because the receipt established the amount of peanuts securing the loan.

In fact, in the spring of 1977 the loan officer left warehouse receipts totaling as much as $1 million on the books for up to two months after being notified that the peanuts were no longer in the warehouse, according to sources familiar with NBG records.

As a result of these actions, Carter Warehouse enjoyed $1 million of uncollateralized credit for up to two months. It is unclear, however, how this advantage was used by Carter Warehouse or NBG.

NBG's books were being examined at the time by the comptroller of the currency. But it is not known if the national bank regulator became aware of apparent preferential treatment given to the Carter Warehouse loan.

Robert Guyton, who became president of NBG after Lance left the bank, refused to comment on any part of The Washington Post story. Robert D. Flynt, the loan officeron the NBG account, who has testified before the Lance grand jury, has repeatedly refused comment.

Collateral Control Corp. President Walter Richey acknowledged in a recent interview that delays in receiving the bank's releases were regarded as so serious that his company had to take steps to remedy the situation, steps he declined to detail.

But sources familiar with NBG records said a top Collateral Control executive wrote a letter in the spring of 1977 telling bank officials that there were serious delays in the transsion of warehouse releases. That letter angered several NBG executives who allegedly were unaware of the problems with the loan. They, in turn, put pressure on the loan officer, Flynt, to get NBG on the record with an admonitory letter to Billy Carter, sources said.

Flynt wrote the letter on June 7, 1977. In it, he told Billy Carter: "At this time we are holding approximately $400,000 in warehouse releases with no funds to cover these releases. You should release no additional peanuts until sufficent funds are in the bank to cover all releases, and no more checks should be written for any reason until there are sufficient funds."

The excerpt appeared in the NBG report of the two outside directors, but without any of the background that prompted it.

White House spokesmen and the president's trustee, Kirbo, have repeatedly blamed the warehouse problems on mismanagement and crop failure.

But according to Agriculture Department figures, the warehouse seemed to be thriving at a time when the loan was beginning to sour. Department figures show that the Carter family business processed 6,800 tons of peanuts in the 1975-1976 growing season, upping that figure to 10,170 tons a year later.

That the booming ware house business did not keep up with its loan payments to NBG renews questions about what the business did with its cash flow. The main question is whether the NBG loan was used, either directly or indirectly, to help finance Jimmy Carter's then financially strapped campaign for the presidency.

The White House has repeatedly denied this, as has Kribo.

The business did fall off sharply from 10,170 tons a year to the 1977-1978-1979 level of 3,800 tons a year, according to government figures.

But this happened after the NBG's commodity loan had nearly run its course. The loan was fully repaid by February 1978.

The more recent troubles at the warehouse are attributed to the arrival of several new and aggressive rival peanut warehousing operations in the area, formerly dominated by the Carters. Area businessmen also say that Billy Carter, who was well-liked by the farmers, was the company's greates asset, and that business fell off asa result of his departure in the summer of 1977. CAPTION: Picture, A forklift operator stacks peanuts inside the Carter Warehouse. AP