The iShares MSCI Brazil Capped ETF (NYSEArca: EWZ), the largest Brazil ETF by assets, is trading lower by almost 1% Thursday as traders digest news that some professional investors have been dumping shares of Petrobras (NYSE: PBR), one of EWZ’s largest holdings.

In the essence of fairness, which is deserved because Brazil ETFs have absorbed their share of criticism in this space, EWZ is up nearly 6% since Feb. 11. Additionally, 1% intraday losses, such as today’s, are not uncommon for EWZ. After all, the ETF has plummeted 35% over the past two years and has a three-year standard deviation of 24.6%. [Bottom not yet in for Brazil ETFs]

Petrobras, Brazil’s state-run oil company and the largest publicly traded Latin American oil company, has been a persistent problem for EWZ for several years. As we have previously noted, Petrobras is the worst-performing major global oil stock over the past five years. The company’s five-year slide now resides north of 84%. Yes, even BP (NYSE: BP), shares of which had to endure the company’s malfeasance in the 2010 Gulf of Mexico oil spill, has outperformed Petrobras over the past half-decade. [Petrobras Pushes Brazil ETF Lower]

Two Petrobras securities combine for nearly 7% of EWZ’s weight, making the stock the ETF’s second-largest holding. Amid an ongoing corruption probe, one that has ensnared Brazilian President Dilma Rousseff, some big-name investors are dumping Petrobras.

George Soros’s Soros Fund Management LLC, BlackRock Fund Advisors and Fidelity Management Research Co. pared stakes in Petrobras during the fourth quarter, reports Rogerio Jelmayer for the Wall Street Journal.

“A Reuters review of a 2009 federal investigation of Petrobras, and interviews with those who conducted it, indicates Rousseff missed opportunities to stop the graft before it erupted into a crisis so big it could push Brazil’s slow-growing economy back into recession next year,” Reuters reported. Rousseff served as Petrobras chairwoman from 2003 to 2011.