The Merval index of the Buenos Aires Stock Exchange fell 11.9 percent on Tuesday, with slumps registered for banks and energy companies.
Tuesday was the second day of trading after the Mauricio Macri administration imposed some capital controls on Sunday.
The volume traded in shares was 1.127 billion pesos (almost US$19 million), on a day in which there were also heavy losses for Argentine companies and bonds listed on Wall Street.
Intervening in the currency market, the Central Bank contained the peso against the dollar, with the national currency closing at 58.48 per greenback.
Elsewhere, the Fitch ratings agency today altered its review of Argentina's sovereign debt rating to "CC" from "restricted default."
The agency, however, lowered the country's ceiling to "CCC", from "B-", citing the recent imposition of capital controls and additional risks.