NY -- Standard&Poor's CreditWire 6/17/97 -- Standard&Poor's today has assigned its double-'B'-plus credit rating to the Republic of South Africa's planned $250 million Yankee issue. The outlook is positive. The rating and outlook are supported by South Africa's: -- Commitment to fiscal and monetary discipline and market-based structural reforms, which the government outlined in its June 1996 medium-term program; -- Manageable external debt burden, which is comparable to other sovereigns in the double-'B' foreign currency rating category; -- Relatively low inflation; and -- Strengthening political stability, underpinned by popular political leadership and social resilience. Creditworthiness remains constrained by: -- High fiscal deficits and public debt burdens, which constrain policy flexibility and economic growth by depressing savings