Business Notes FINANCIAL MARKETS

Among wealthy Brazilians, such pastimes as sunbathing and the samba have been joined lately by stock-market speculation. Since May 1987 the bourse in Rio de Janeiro has jumped almost 400%. Lebanese immigrant Naji Robert Nahas, who alone accounted for nearly half of the market's trades in recent weeks, brought Brazil's bulls to a halt last week after several brokerage houses discovered that $31 million of his checks had bounced on them. To avoid a bearish stampede, the Rio and Sao Paulo markets were forced to close last Monday. When trading resumed the next day, the benchmark I.B.V. index plunged 9% and ended the week down 32%. Nahas is a past master of shady finance: three years ago the U.S. Government fined him $250,000 for his role in manipulating silver prices.