BUENOS AIRES, Sept 12 (Reuters) - Argentine bond prices lost ground on Friday as global economic jitters made investors risk shy, but stocks rose as heavyweight issues related to the oil sector reacted to slightly higher crude prices.
Sovereign bonds traded on the local market fell 0.7 percent on average, but trade volume was weak. The 2017 Bonar in dollars slumped 2.4 percent as investors shed emerging markets assets due to uncertainty over the world economy.
"The market is still dealing with unwinding of positions. There aren't too many sales but the market keeps bleeding," said one bond trader, who asked not to be named.
The MerVal benchmark index .MERV gained for a third day in a row, adding 2.13 percent to 1,647.65 points in heavy volume of $44 million. Of active issues 56 advanced, 40 declined and 10 were unchanged.
Tenaris, which makes steel pipes for the oil industry (TENA.BA), jumped 4.4 percent to 74.2 pesos per share as crude oil prices inched up because Hurricane Ike was threatening the Texas oil industry.
Tenaris has a 14 percent weighting on the Merval.
"The oil price recovery is pushing up the market through Brazil's Petrobras and steel company Tenaris," said a trader.
Buenos Aires-listed shares of Brazilian state oil firm Petrobras APBR.BA soared 9 percent to 71.4 pesos per share.
After a steep four-day slide that took the peso to three-month lows, the currency held its ground against the dollar as the central bank injected greenbacks into the market.
In informal trade between foreign exchange houses, as measured by Reuters, the peso closed flat at 3.1175/3.1225 per dollar ARSB=. In formal trade between banks the peso weakened only 0.8 percent to 3.0800/3.0825 per dollar ARS=RASL.
"Central Bank dollar sales began as soon as the market opened to assure liquidity and to blaze the trail for traders," said Fernando Izzo, a trader at ABC foreign exchange business. (Reporting by Walter Bianchi, writing by Fiona Ortiz)