Col. Muammar Qaddafi's tens of millions of dollars in aid to revolutionary and alleged terrorist groups is dwarfed by another tally of less publicized investments.

"There are obviously a lot of things they are doing on the economic front which we welcome," said one senior State Department official.

Most of Libya's foreign investments from its mounting oil surplus are channeled through the Libyan Arab Foreign Bank. This year, with expected oil revenues of $15.4 billion - double last year's revenues - Libya will have even more money to place abroad.

Tripoli's current investments include:

More than half a billion dollars in loans to the World Bank, more per capita than the United States and some other industrial countries are making available to the leading international aid institution.

A recently negotiated guaranteed loan of $100 million to the Central Bank of Turkey, the focus of a recent bailout operation engineered by the leading Western powers, including the United States and West Germany.

Participation in a $100 million copper mining project in Zaire, also the object of a massive U.S. aid program.

A $460 million investment in Fiat, the Italian auto manufacturing giant.

At the Libyan Arab Foreign Bank headquarters here, assistant manager Mohammed Ilyas explained the institution's role.

"We are always looking for good investments," he said, adding that Libya in the future is not likely to enter into a single deal as large as that with Fiat. As an illustration, Ilyas said the bank has just completed a $100 million investment in the Arab-Latin American Bank.

While most of the Libyan Arab Foreign Bank's placements are geared to earning a profit, it also has a network of what Ilyas called "foreign aid development assistance loans." These fan across Africa and the Arab world, including countries such as Gambia, Guinea, Mauritania, Somalia and Niger. CAPTION: Picture, Libyan street markets have little to sell. Despite the nation's oil riches, consumer and capital goods remain scarce in Libya's centrally planned economy. By J. P. Smith - The Washington Post; Graph, U.S.-Libya Bilateral Trade, By Richard - The Washington Post