Exchange-traded funds tracking the financial sector were among the strongest performers in a wild week that was highlighted by JPMorgan Chase ( JPM) setting plans to buy Bear Stearns ( BSC) and more attempts by the Federal Reserve to restore the health of the financial markets. Among the big ETF winners were Ultra Financials ProShares ( UYG) and iShares Dow Jones U.S. Financial Services ( IYG), which surged 19.3% and 11.8%, respectively, for the week. The Vanguard Financials ETF ( VFH) and the iShares Dow Jones U.S. Financial Sector ( IYF) each climbed more than 9%. Bundled securities tracking oil and gold, however, were among the losers. The Oil Services HOLDRs ( OIH) lost 5% for the week, and the PowerShares Dynamic Oil & Gas Services ( PXJ) fund gave back 5.3%. The iShares Dow Jones U.S. Energy ( IYE) and the PowerShares DB Energy ( DBE) were off 2.9% and 2%, respectively. As for funds tracking gold, the Market Vectors Gold Miners ( GDX) sank 10.8% since Monday. Losing more than 6% were the PowerShares DB Gold ( DGL), the iShares COMEX Gold Trust ( IAU) and the streetTRACKS Gold Shares ( GLD) funds.