Trade between the U.S. and Vietnam was a minuscule $18.2 billion in 1996--and U.S. foreign direct investment in the southeast Asia nation was only $60 million. But those numbers could change soon. Within the next few weeks the Vietnamese government and the Overseas Private Investment Corp. (OPIC), a federal agency that helps U.S. firms manage the political and financial risks of investing in developing countries, are expected to ink an agreement making the agency's programs available in Vietnam. Projects totaling more than $900 million could be implemented once OPIC support becomes available. President Clinton has already waived the Jackson-Vanik amendment to the 1974 Trade Act, setting the stage for resumption of OPIC programs in Vietnam.