A 35% rise against the dollar of the Brazilian real and a rise of 80% of the Brazilian Bovespa index in 2009, following quickly after the global financial crisis, shows the big swings in emerging markets stock and currency values. Brazil is a big exporter of agricultural and mining commodities. Brazilian government is concerned about short term investors who are piling into investments there, but could pull out quickly in another crisis. The government imposed a 2% tax on foreign investments- designed to reduce currency volatility and discourage short term speculative investors. A slowdown in demand for commodities from China or other countries could quickly reverse this rise. And a rise of this proportion in so short a time, coming on the heels of a financial crisis, shows the nature of swings in the global economy that are of increasig concern today. In October 2008 Brazil's currency lost a third of its value compared to August 2008, and the Bovespa index fell by 50%. The central bank had to use its currency reserves to prevent a severe drop in the value of the real. Short term investors were pulling money out of the stock market resulting in dollar outflows, and many Brazilian companies that had bet against the dollar in currency derivative contracts suffered huge losses. The situation was similiar in Mexico. It shows the fragility of economies depending on commodities exports, and the lack of mechanisms to track these derivatives and to restrain speculative short term investors. ...