RE:About currency exchange... As of Novermber Knight had already converted most of what it needed for the acquisition. This is from the Q3 financials.
Subsequent to September 30, 2019, the Company entered into forward contracts which is the equivalent to holding BRL 820,662 in terms of financial risk. The forward contracts will be used to fund the acquisition of GBT. As a result, the Company is exposed to additional currency risk due to fluctuations of the BRL relative to the Canadian dollar.
The total enterprise value is 1.318 billion BRL, so Knight could only possibly benefit from the remaining ~500 million BRL declining. But it's also possible that Knight converted more CAD to BRL since then, so we can't really know if they are benefiting or not. I suspect they didn't convert more, meaning they essentially hedged 40% of the purchase price, ewhich would make sense. But the point is we don't know.
What we do know is that most estimates for Knight's future EBITDA, EBIT, earnings, and cash flow, were all based on the exchange rate at the time of the acquisition, which was $1=3.14 BRL. Since the exchange rate is now $1=~3.33 BRL, Knight's 2020 earnings are much lower.
At the time of the acquisition, analysts were expecting Knight to have a run rate of like $50 million once they closed on the rest of GBT. But that was based on the old exchange rate. Now, EBITDA is more likely $45 million. I don't think that greatly affects Knight long-term so I think the current drop is overdone, but currency is going to be a big deal for Knight from now, and if the Real drops lower (the chart is pretty well straight down to the right so it probably does), Knight's share price will probably keep going down to. If you can invest based on what the share price will be 10 years from now, that should make you happy.