I'm not a currency trading expert, but i suspect that currency speculation has nearly as much to do with manipulating the economy of a country as it does about economic prospects of said country.
When Lula first got elected international speculators freaked the F out, thinking he was a communist, and crushed the Real vs the Dollar, rising to previously unimagined peaks of about R$4 to the US$. It was so stark that hotels refused to give me the official exchange rate at the time, saying "this is just a phase, it will come back to normal soon". Normal was R$3:1.
During Lula's presidency the US$ fell vs the R$ to as low as 1.8:1, IOW, speculators thought Brazil's economy was crushing it. This coincided with Lula drastically reducing abject poverty by essentially just giving money to poor people, and also strongly seeking to reduce slavery and give the federal police more power to hunt down corruption (the two are linked). I don't think the traditionally corrupt power structure (TCPS) liked this all that much.
Fast forward: the TCPS orchestrated the impeachment of a possibly marginally corrupt politician, who also happened to be a woman, Dilma, in what is only explainable by calling it a coup. This brought the unimaginably corrupt, yet firmly entrenched in the TCPS, Vice-president to power. Since then it has been an unending flood of corruption, abuse of power, un-investigating those in Congress under investigation for abject thievery from public coffers, and general economic malaise. The middle class is shrinking after years of expansion under Lula and Dilma, abject poverty is on the rise, and wealth among the TCPS is also on the rise: funny how that works.
And the coup de grace, and reason for why i thought to write this: the exchange rate with a “strong-for-the-economy, at-least-i’m-not-a-commie” president is now at R$4.1 : US$1, worse now than when speculators thought that the dirty commie Lula was gonna nationalize everything and destroy their beloved easy access to raw materials that Brazil supplies with abundance.
Glenn Greenwald gave a rather interesting perspective as to why the TCPS orchestrated the coup: the Worker's Party (TP) rose to power and created a genuinely decent economy by giving money from the rich to the poor, which helped Brazil weather the economic collapse in 2008 much better than the US. However, Lula and Dilma are not from "the club", and their presence in power was only tolerated as long as they were able to deliver results to the TCPS, which they did, in spades, by applying neoliberal style policies along redistributionist policy. But the roaring economy began to slow just a little too much for the tastes of the TCPS, and Dilma was not a skilled coalition style deal-maker, and the TCPS sensed its moment and pounced. And their pounce was incredibly effective, discombobulating the populace, creating fear and confusion, and they directed the anger at those least responsible for creating the mess.
So, how do you feel about beating on your frying pans now “os panelistas do Fora Dilma”? You were completely duped by propagandist b.s. Your acceptance of the Workers' Party as the sole and unique source of corruption in Brazil has given rise to the most corrupt president possible, the reduction in investigations and convictions of actual corruption, and could quite possibly lead to a dyed-in-the-wool military dictatorship worshiping fascist becoming President in the form of Bolsonaro. Congratulations, you played your part as puppets to the masters perfectly. Your screaming in the streets gave cover to one of the most dramatic transfers of your own political power and wealth to those who most covet your absolute destruction and misery.