BUENOS AIRES, Oct 23 (Reuters) - Argentine stocks closed up on Tuesday, buoyed by global market gains in a session marked by selectivity and heavy volume, traders said.
The MerVal index .MERV of 25 leading stocks advanced 0.77 percent to 2251.93 points, for a 2.92 percent rise since the beginning of the month.
"The MerVal joined the upward trend we saw on external markets through its stock in the oil and power sectors," said Marcelo Paccione of ConsultCapital.
Leading gains were Brazilian state oil firm Petrobras APBR.BA, which climbed 3.8 percent to 132 pesos per share, and energy group Pampa Holding PAM.BA, which closed up 3.37 percent at 2.76 pesos per share.
"Even more than the gains, the heavy volume stood out today as investors reshuffled their portfolios ahead of quarterly earnings reports," added Paccione.
Trade volume on the broad stock market totaled a robust 154.3 million pesos ($47.9 million), and of active shares, 62 advanced, 28 declined, and 13 were unchanged.
Bond prices on the local market also recovered, rising 0.3 percent on average as private investors capitalized on a recent drop in prices <AR/BONOS>.
The peso currency weakened as traders continued to stock up on dollars ahead of Sunday's presidential election.
The peso gave up 0.31 percent to close at 3.2175/3.2200 per dollar ARSB= in informal trade between foreign exchange houses, as measured by Reuters.
In formal interbank trade, where the central bank regularly intervenes to keep the peso steady, the currency weakened by 0.16 percent to 3.1725/3.1750 per dollar ARS=RASL.