Brazilian Banks - Downside?

Hey guys,

I am surprised I did not see these mentioned much - These are Brazilian bank tickers -- VIV ITUB and BBD. Monthly payers, yield for example.of ITUB is 6% or so, 37% Price appreciation YTD and in a minor dip at this moment.

Is there severe tax implications here? Some quick googlong did not reveal much. Why is this not more popular with income investors?