What: Shares of Brazilian miner Vale SA (NYSE:VALE) jumped 11% late in trading on Friday, as investors speculated about the future of the company, Brazil, and interest rates.

So what: Brazilian stocks, in general, rose today, as metals prices were higher, and investors bet the Federal Reserve wouldn't raise interest rates soon. Iron ore prices climbed, as well, after a rough past three months for the commodity. 

There was also speculation that CEO Murilo Ferreira will be ousted as part of the political upheaval taking place in Brazil. Ferreira took the job in 2011 as President Dilma Rousseff took power. Now that she's been ousted from power, Vale may be looking for a new leader. 

Now what: Metals stocks have been incredibly volatile this year, and Vale's shares are showing the ups and downs, as well. But investors shouldn't focus too much on this short-term speculation, and should look at the long-term trends. We're seeing the metals market oversupplied by Asian competitors, and demand in Asia simply isn't keeping up. That's led to falling commodity prices, including iron ore. It's that weakness that would keep me out of the stock, even if the news hitting the wires is mildly positive today.

Travis Hoium has no position in any stocks mentioned. The Motley Fool owns shares of Companhia Vale Ads. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.