LONDON -- Standard&Poor's CreditWire 9/17/97 -- Standard&Poor's today assigned its triple-'B'-minus long-term counterparty rating to the National Bank of Greece S.A. (NBG). The bank's 'A-3' short-term counterparty rating is affirmed. The long-term rating outlook is stable. The ratings reflect the bank's size and powerful position in the Greek financial markets, which provides strong implicit support from the Greek State. In addition, the ratings reflect National Bank of Greece's strong liquidity and the comprehensive rehabilitation program that is being implemented by the bank's management. At the same time, NBG's creditworthiness is somewhat constrained by weak profitability, asset quality and capitalization. NBG is the largest bank in Greece and holds a prime position in the country's financial markets,