This Week's ETF Winners & Losers

Exchange-traded funds tracking oil were some of the worst performers this week as a surging U.S. dollar sharply pulled down oil prices following a days-long tear into record territory.

Oil started the week off with a bang after news broke that Nigerian militants had attacked two oil pipelines, but the crude rally cooled after the greenback staged a big recovery Thursday. Futures took back a great deal of those losses Friday as fresh supply worries cropped up, but oil-related stocks ended up beaten down for the week.

Oil Services HOLDRs OIH slid 3% for the week, the PowerShares Dynamic Oil & Gas Services PXJ fund was down 1.7%, and the iShares Dow Jones U.S. Energy IYE declined 0.8%.

Bundled securities tracking gold-related shares also fell over the past five sessions as the metal followed oil downward Thursday amid a stronger dollar.

Since Monday, the Market Vectors Gold Miners ETF GDX has tumbled 9%, the iShares COMEX Gold Trust IAU has dropped 4%, and streetTRACKS Gold Shares GLD has given up 3.7%.

On the flip side, ETFs tracking the financial sector clambered upward as investors continued to find clues that the group has weathered the credit storm and is poised for recovery. Merrill Lynch MER, for instance, maintained its dividend, indicating that it now has a healthy cash pile and can thus afford to do so. The stock added 4.8% for the week.

The week also saw National City NCC slashing its dividend, posting a quarterly loss, and launching a heavily discounted equity sale in an effort to raise capital, and Ambac ABK swung to a big shortfall as well. Nat City plummeted 24.1% over the past five sessions, and Ambac tanked 35.5%. Still, the sector was generally in better shape at the end of the week.

The Financial Select Sector SPDR XLF and the iShares Dow Jones U.S. Financial Sector IYF ETF each tacked on 1.9% for the week, and the Ultra Financials ProShares UYG climbed 3.6%.