Investigators looking into the Philippine sugar industry have concluded that associates of deposed president Ferdinand Marcos diverted more than $1 billion from sugar producers during the past decade, according to a document prepared for the new government of President Corazon Aquino.

Preliminary findings indicated that the sugar industry was one of the major sources of funds removed from the Philippine economy during Marcos' 20-year rule. Investigators said later that the amount of diverted funds may exceed that generated by the coconut industry, which for years ranked as the country's leading foreign-exchange earner.

The initial findings were assembled by a team from the sugar industry working under the auspices of the revamped Philippine Sugar Commission, known as Philsucom. It is to assist an eventual full-fledged investigation by a presidential commission that seeks to recover Marcos' "ill-gotten wealth."

A four-page summary of the findings lists 21 "anomalies" in the sugar industry that are said to have resulted in total losses of at least $1.15 billion from 1975 to 1984.

The summary lists the main beneficiary of the "anomalies" as the National Sugar Trading Corp. Essentially a trading monopoly, it was established by Marcos in a 1974 decree and headed by a close associate, Roberto Benedicto.

The summary does not go into details of where this lost money went, but investigators said they believe the funds extracted from the sugar industry through a variety of schemes represented one of the largest single sources of billions of dollars alleged to have been channeled abroad by Marcos, his family and associates.

The industry also was used as a source of "political payoffs" to a broad range of people whom Marcos wanted to reward, including politicians of his ruling party, military officers and even Moslem rebels who surrendered, as well as to his relatives and friends, the investigators said.

During the probe, investigators said they looked into activities of Gen. Fabian Ver, the former armed forces chief of staff; Pacifico Marcos, the ousted president's brother; Marcos' wife Imelda and another close associate, Antonio Floirendo, who they said they believed benefited as middlemen in the sugar-trading monopoly.

Probers said Imelda was a silent partner with Floirendo in a New York sugar refinery, the Revere Sugar Corp., that made millions of dollars by underpaying for Philippine sugar.

The "plundering" of the sugar industry, as it was described here by Mary Concepcion Bautista, a member of a presidential commission investigating Marcos' wealth, has assumed a domestic significance beyond the loss of a huge amount of revenue over the years, according to industry sources and Aquino government officials.

It is seen as a factor in the industry's severe depression which was compounded by low world prices. The result has been widespread unemployment affecting as many as half the country's 600,000 sugar workers, malnutrition that has claimed the lives of hundreds of children on the sugar-producing central island of Negros, and a dramatic growth of Communist insurgency in sugar-producing areas.

While drastic decreases in the world sugar price in recent years would have caused a major scaling-down of the Philippine sugar industry in any event, critics of Marcos' administration long have charged that most of the dislocations of the current crisis probably could have been avoided if not for damage they attribute to Marcos and his associates.

Manipulation of the sugar industry "has a direct connection" with the poverty, hunger and rebellion on the island of Negros, said Bautista.

According to Fred J. Elizalde, a former Marcos appointee to the government sugar-trading monopoly, the ravaging of the sugar industry took place largely during the late 1970s. Elizalde is officer in charge of the new Philippine Sugar Commission.

"The rip-off was much greater and more extensive than anybody imagined at the time," Elizalde said, referring to the report's findings.

According to investigators, the major beneficiary of the scams, Benedicto, is a former law school classmate of Marcos who was appointed to head Philsucom in 1977. Benedicto has been identified by the Presidential Commission on Good Government, set up by Aquino to investigate and recover Marcos' "ill-gotten wealth," as the closest and longest serving Marcos "crony."

Investigators said he was instrumental in funneling Marcos' wealth overseas, investing in ventures in the United States and traveling regularly to Switzerland during the 1972-81 years of martial law.

Government investigators say Benedicto fled about the same time as Marcos and is believed to be in the United States.

Philsucom was created by Marcos to promote the development and stability of the sugar industry by consolidating all sugar-related governmental and regulatory functions under one agency. In 1974, Marcos also decreed the establishment of the Philippine Exchange Co., called Philex, to act as the country's single sugar trading arm. The decree permitted Philex to collect commissions from sugar producers amounting to 2.5 percent of gross sales and to put profits into a special government fund "subject to the disposition of the president for public purposes."

In 1977, Marcos issued another presidential decree creating the National Sugar Trading Corp., known as Nasutra. Also headed by Benedicto, Nasutra then took over the sugar trading functions of Philex as the sole agency for buying and selling the commodity.

Around the same time, an allocation system was established in which sugar for the domestic market was allotted, essentially by Marcos, to industrial users and "preferred" traders, according to industry sources.

Meanwhile, Philsucom gained control of the bankrupt Republic Bank, establishing it as Republic Planters Bank to provide financing for the sugar industry. It also acquired sugar refineries under a subsidiary to consolidate control.

According to the preliminary findings, one major source of losses was a "longer marketing chain" created by the monopoly, in which "paper traders" were favored with allocations empowering them to buy and sell sugar. Often they simply sold their rights to actual traders at a markup. The summary estimated total losses from this practice at $204 million from 1975 to 1984.

"By and large, these were straight handouts to favored people," said one leading sugar industry official of the allocations. "They were political payoffs, a way of keeping his people happy. These were people Marcos needed to maintain political power."

Excessive trading costs deducted by Nasutra from proceeds of sugar producers cost about $245 million over the period, the summary said. Kickbacks from purchase of sugar mills, mainly from Japanese suppliers, totaled $60 million to $90 million, it said.

As a result of a "participatory contract" between Nasutra and Floirendo's Revere Sugar Corp., the Philippine sugar industry lost $110 million from 1975 to 1980, the summary reported. It said producers were consistently paid 2 cents a pound less than the prevailing price for their sugar exported to the refinery through the monopoly.

A discrepancy between the revenue that Nasutra should have generated from total sugar exports for the 1984-85 crop year and the amount actually paid to producers represented a loss of about $116 million, the summary said.