Argentina's peso currency crashed Monday, closing 15,27 percent weaker at 53.5 per United States dollar after slumping some 30 percent to a record low of 65 to a dollar earlier in the day after Argentinian President Mauricio Macri suffered a loss in a primary election, Reuters reported, Trend reports citing Sputnik.
The Merval index plunged to 27,530.80 points, a drop of 37.93 percent, as some major stocks lost up to 50 percent, AP said.
Argentina's credit default swap - or the cost of hedging bonds against sovereign default - soared to a multiyear high.
Argentine 5-year credit default swaps (CDS) jumped to 1,955 bps, nearly doubling from Friday's close of 1,017 bps, according to data from IHS Markit.
There could be an even stronger degree of market volatility if final results show that Fernandez has enough support to clinch the presidency in October's first round, analysts said.
Sunday's defeat to opposition candidate Alberto Fernandez is a result of the economic hardship South America's second-largest country has endured recently, Macri told reporters at the Casa Rosada presidential palace in Buenos Aires.
Fernandez has suggested he would seek to "rework" Argentina's standby agreement with the International Monetary Fund. Markets are also anxious over de Kirchner, whose years as president from 2007 to 2015 were marked by a balance of payments crisis, interventionist state policies, currency controls and protectionism.
However, she is embroiled in a dozen corruption investigations, the first of which has already gone to trial, and is a controversial figure.
"This is just a taste of what's going to happen" if the populist opposition wins the election, Macri warned on Monday.
Speaking in southern Brazil, Bolsonaro warned, "we don't want that: Argentine brothers fleeing over here, seeing how very bad it could get if the result of the vote yesterday is confirmed in October", he said.
"If the leftists return to Argentina, we could have a new Roraima", Bolsonaro said, referring to the state where thousands of Venezuelans have crossed to Brazil Cristina Kirchner, who was president from 2007-2015 after succeeding her husband, has been tainted by corruption scandals but remains popular.
"The Kirchnerist alternative has no credibility in the world".
Speaking before the worst of the day's losses were known, Fernandez blamed the market reactions on government policies.
"The markets are giving warning that the government has put itself in a position it can not respond to", Fernandez told Radio 10.