BUENOS AIRES, Oct 17 (Reuters) - Argentine stocks rose sharply on Friday, buoyed by gains in energy-related shares as crude oil prices rebounded, traders said.
The benchmark MerVal index .MERV ended 2.53 percent higher at 1,216.02, after rising as much as 5.4 percent earlier in the session when U.S. stocks temporarily surged.
The MerVal is down 24 percent since Oct. 1 and 43.5 percent since the start of the year.
"It was a volatile day tied to Wall Street and the strength of shares in Tenaris and Petrobras," said Guido Macchi, a trader at Macchi brokerage.
Brazil's state energy company Petrobras (APBR.BA) gained 5.47 percent to end at 43.40 pesos a share in Buenos Aires, while Tenaris (TENA.BA) -- which makes steel tubes for the energy industry -- gained 5.19 percent to 39.50 pesos.
Trade volume on the broad market was a moderate $25.9 million. Of active shares, 36 advanced, 23 declined, and 7 were unchanged.
The Argentine peso closed mixed. It firmed 0.30 percent to 3.31/3.315 per U.S. dollar ARSB= in informal trade between foreign exchange houses, as tracked by Reuters.
But in formal trade between banks ARS=RASL, where the central bank intervenes directly to hold the peso steady, it slipped 0.23 percent against the dollar to 3.21/3.2125.
Argentine bonds traded locally continued falling on Friday, dropping 1.7 percent on average in over-the-counter trade to accumulate losses of about 5 percent in the week.
The biggest loser among the most liquid bonds was the dollar-denominated Boden 12 ARBODEN12D=RASL, which sank 4.4 percent according to the ask price, amid rumors it could be included in a debt swap the government is planning that primarily targets so-called guaranteed loans.
Argentine debt spreads widened 23 points to 1,395 basis points above comparable U.S. Treasuries, according to the JPMorgan emerging markets bond index 11EMJ. (Reporting by Jorge Otaola and Walter Bianchi; Writing by Hilary Burke; Editing by James Dalgleish)