Assembling a list of U.S. corporations in South Africa is not a popular or easy task.

For several years, the U.S. Consulate General in Johannesburg put together such a list but stopped compiling it in 1983 because, "It was incomplete and not representative," said Susan Keough, assistant country officer for South Africa at the U.S. State Department.

Keough said companies provided information only on a voluntary basis, which resulted in a very "scrappy list." Some observers say the State Department's list became a "hit list" used by antiapartheid groups to pressure American companies to stop or limit their business in South Africa.

"I think the State Department wanted to disassociate itself from the directory," said David Hauck of the Investor Responsibility Research Center. "Their job is to try to improve or promote relations between government and businesses, and the directory was having the opposite effect."

The center, a nonprofit organization, took over the task of assembling the list and in 1984 published Foreign Investment in South Africa, a directory of U.S., British and Canadian companies with investments in South Africa and on South African lending policies of the 100 largest U.S. banks. The directory is the most comprehensive list of U.S. corporate involvement in South Africa. Through a survey done by the center's South Africa Review Service, it identified 284 U.S. companies with direct investments in South Africa or Namibia, a territory administered by South Africa. The directory also profiles the operations of more than 160 Canadian and British companies.

The directory costs $100, and so far, 1,500 have been sold. The list, however, does have some weaknesses. For instance, of the 100 banks surveyed by the center, 22 declined to provide information on their lending policies. In terms of actual lending, 32 banks refused to give the center any information on outstanding loans to South Africa.

The Investor Responsibility Research Center was founded in 1972 at a time when many activist groups began to urge investors to scrutinize the activities of the companies they had stock in. The center says its function is "to conduct research and publish impartial reports on contemporary social and public policy issues, and the impact of those issues on major corporations and investors."

The center's work is financed mainly by annual subscription fees paid by more than 170 investing institutions. Its subscribers are banks, trust and insurance companies, investment and management firms, foundations, hospitals, universities, church groups and pension funds.