By Taos Turner 
 

BUENOS AIRES--Argentine stocks slid Tuesday while GDP warrants declined and the peso continued to weaken.

The Merval stock index slid 0.33% to 4,631.85 in volume totaling ARS109 million ($19 million).

The power company Pampa Energia SA (PAMP.BA, PAM) led the gains for a second day, rising 4.8% to ARS1.74. Pampa's electricity distributor, Edenor (EDN.BA), also gained, rising 1.5% to ARS1.33. Both companies had surged Monday on speculation that Argentina's government will raise utility rates sometime after a congressional election in late October.

Grupo Financiero Galicia SA (GGAL.BA, GGAL), the day's most-traded stock, fell about 2% to ARS7.73.

Steel producer Tenaris SA (TEN.MI, TS) fell about half a percent to ARS219.

GDP warrants, or securities whose performance are tied to economic growth, declined. The TVPE GDP warrant fell 0.63% to ARS95 while the TVYO warrant fell 0.79% to ARS75.20.

The Argentine peso weakened to ARS5.7420 against the U.S. dollar on the regulated MAE foreign-exchange wholesale market, versus ARS5.7315 the previous session.

The central bank intervenes in the exchange market daily to buy dollars and build its foreign currency reserves, while gradually weakening the peso to help exporters.

In the underground market, the peso traded for ARS9.31 to the dollar versus ARS9.30 the previous day, according to the newspaper El Cronista, which publishes rates collected from black-market traders.

Strict capital controls that limit the amount of foreign currency Argentines can purchase legally have fueled a parallel illegal market for dollars where people pay a steep premium for the U.S. currency.

Write to Taos Turner at taos.turner@wsj.com