BUENOS AIRES, Dec 20 (Reuters) - Argentine stocks closed higher on Thursday after trading lower much of the day, rising as bimonthly options expired and boosted by a turnaround in global markets, traders said.
The MerVal index .MERV of the 25 leading stocks rose 0.47 percent at 2,140.31 points. The index is up 2.4 percent since the start of the year.
"The closing of positions as options expired sparked upward movement in the MerVal during the last hour of the session, which corresponded to a better external context," said Marcelo Paccione, analyst at ConsultCapital consultancy.
"The gains were supported by shares linked to the options contracts, like Grupo Financiero Galicia, Pampa Holding and Molinos," Paccione said.
Grupo Financiero Galicia GFG.BA closed 0.45 percent higher at 2.25 pesos a share, while shares in energy group Pampa Holding (PAM.BA) ended flat at 2.58 pesos.
Food company Molinos (MOL.BA) jumped 8.8 percent to 11.1 pesos after the company bought 83.3 percent of rival Grupo Estrella QUE.BA.
Broad market volume moderate at 91.8 million pesos ($29 million). Among active issues, 28 advanced, 26 declined and 23 closed flat.
Government bond prices rose a modest 0.2 percent on average in a quiet session, traders said.
The biggest gainers were the Par bond denominated in dollars, which rose 1.5 percent, and the Boden 2012, which rose 1.1 percent <AR/BONOS>.
"Investors continue to be wary of risky investments, especially at this time of year when they have to close their annual positions," a trader said.
The peso currency, which is regulated by the central bank, closed 0.16 percent weaker at 3.1350/3.1375 per dollar ARS=RASL in formal interbank trade.
In informal trade between foreign exchange houses, as measured by Reuters, the peso ended flat at 3.1575/3.1600 per dollar ARSB=. (Reporting by Walter Bianchi; Writing by Hilary Burke; editing by Gary Crosse)