Just so no one thinks this just accidently happen but was in the works for a while. This from 2 1/2 years ago:
Market Watch Feb. 17, 2009 - “Soros, through his Soros Fund Management LLC, reported holding 36.8 million American depositary receipts of the Brazilian oil company known as Petrobras as of Dec. 31 - a holding valued at about $900 million at the time.”
http://www.marketwatch.com/story/soros-reports-735-increase-petrobras-stake