As of 17.48 GMT, Merval was down 14.07 percent to 22,510 after rising 6.45 percent to 26,195.41 on Monday.
The index rose to an all-time high of 44,470.76 on August 9, but lost as many as 38 percent on August 12 after the opposition's unexpected victory in the primaries. The presidential election in the country is set for October.
At the same time, the national currency's exchange rate has not changed. Banco Nacion, the country's largest state bank, sells US dollars at 57 pesos, the other large banks sell it at 58-60 pesos.
The Central Bank of Argentina has already taken a number of measures to support the financial market. Since August 30, it has introduced capital controls, requiring banks to obtain preliminary authorization to distribute their earnings abroad. It has also decided to restrict large export companies’ access to Argentine peso in an effort to make them sell dollars.
Since the announcement of the preliminary elections results in mid-August, Argentina’s economy has faced a downturn which resulted in a sharp peso drop and prompted international credit rating agencies to downgrade the rating of Latin America’s third-largest economy.