What happened

Argentina's stock market imploded on Monday, with shares of some of the South American country's best-known New York Stock Exchange (NYSE)- and Nasdaq-listed stocks falling as much as 55% in a day. ­Today, though, things are looking a bit different.

Shares of Argentine utilities stocks Pampa Energia S.A. (PAM 2.99%) and Central Puerto S.A. (CEPU 0.36%), as well as banker Grupo Supervielle S.A. (SUPV 3.22%) all surged in Thursday trading, up 12.4%, 13.2%, and 16.6%, respectively, as of 2:30 p.m. EST.

Argentine currency in notes and coins.

Image source: Getty Images.

So what

Why the big change from Monday to today?

On Monday, investors panicked after seeing results from the Argentine Presidential primary showing a very real likelihood that the economic reforms instituted by President Mauricio Macri will be rolled back in October if Peronist challenger Alberto Fernandez (and his running mate Cristina Kirchner, the former Argentine president) win the general election. Worries over a deepened recession, a weaker Argentine peso -- and the effects these will have on Argentine companies' profits when translated into dollar terms -- sparked panic among investors, who sold off Argentine stocks en masse.

But investors aren't the only ones panicking. 

This morning, in an eight-minute-long nationwide broadcast, incumbent President Macri told his constituents: "I heard what you wanted to tell me on Sunday. ... I understand your anger, your tiredness." And responding to said anger and tiredness, he promised to implement a series of "relief" measures, including tax cuts, price freezes on gasoline, and welfare subsidies to ease voters' pain... and maybe, just maybe, make them more likely to vote for him in October.

Result: Investors are rethinking the inevitability of a Fernandez/Kirchner administration and giving shares of Pampa Energia, Central Puerto, and Grupo Supervielle the benefit of the doubt.

Now what

On the one hand, that seems like it should be a good thing for investors: The chances of the "reform" candidate remaining in office just spiked. On the other hand, if the President goes too far with his pandering, even a second Macri administration might not look too much different from what we'd see if Fernandez were to win in October.

When you get right down to it, it's not so much the name on the ballot that matters to the future of Argentina's economy and its stocks -- but the policies that the winner institutes in October, in 2020, and in the four years to come.

As of today, it still looks like those policies are taking a turn for the worse.