(Corrects percentage fall in first sentence to 12.14, instead of 12.4)
BUENOS AIRES, Oct 15 (Reuters) - Argentine stocks plunged 12.14 percent on Wednesday, marking their biggest one-day percentage drop in 10 years as fears of a global recession seized investors.
At the same time, bonds traded locally and the Argentine peso lost ground.
The MerVal index of leading shares .MERV ended at 1,185.73 points, erasing Tuesday's 10.99 percent rise. The MerVal is at its lowest level since November 2004.
Global market losses steepened after U.S. Federal Reserve Chairman Ben Bernanke said the economy faces a significant threat from credit market turmoil.
"Bernanke's remarks sparked greater fear of an economic recession, which greatly affected the markets," said Jorge Alberti, an analyst at Elaccionista.com online brokerage.
The Dow Jones industrial average .DJI ended down 7.87 percent and the Brazilian Bovespa .BVSP was trading more than 13 percent lower when the MerVal closed.
Trade volume on Argentina's broad stock market totaled a brisk $45.4 million. Of active shares, 92 declined, 6 advanced and 5 were unchanged.
In informal trade between foreign exchange houses, as tracked by Reuters, the Argentine peso slumped 1.08 percent to end at 3.2850/3.29 per U.S. dollar ARSB=.
In formal trade between banks ARS=RASL, where the central bank intervenes directly, the peso slipped 0.16 percent against the dollar to 3.1975/3.20.
Argentine bonds traded locally fell 3.8 percent on average in over-the-counter trade, pressured by a 9.7 percent drop in the price for dollar-denominated Bonar 2017s ARBONAR17D=RASL, according to the ask price.
Local debt prices are down 22 percent since Oct. 1 amid global market turmoil.
Argentine debt spreads against similar U.S. Treasuries widened 125 basis points to 1,367, according to the JPMorgan emerging markets bond index 11EMJ. (Reporting by Jorge Otaola and Walter Bianchi; Writing by Hilary Burke; Editing by Leslie Adler)