This Week's ETF Winners & Losers

Exchange-traded funds tracking the financial sector were among the biggest winners this week, propelled by the Federal Reserve's decision to cut its overnight lending rate by another quarter-point to 2%.

The Ultra Financials ProShares UYG had a particularly good week, surging 5.2% since Monday.

At the same time, the Financial Select Sector SPDR XLF, the Vanguard Financials ETF VFH, the iShares Dow Jones U.S. Financial Sector IYF fund and the iShares S&P Global Financials IXG ETF each added 2.3% or more.

The central bank provided further cushion to financials Friday when it ratcheted up its term auction facility by 50% to $150 billion, meaning banks will have that much more money available for borrowing.

Since Monday, two of the Dow's financial components -- Bank of America BAC and JPMorgan Chase JPM -- added 3.9% and 1.8%, respectively, though Citigroup C ticked 0.8% lower, weighed down by this week's news that it would offer $4.5 billion in stock.

Suffering the flip-side of the Fed's decision were commodities-related ETFs. Among the worst-performing energy ETFs were Oil Services HOLDRs OIH, PowerShares Dynamic Oil & Gas Services PXJ, United States Oil USO and iShares Dow Jones U.S. Energy IYE. All have sunk at least 2.1% apiece over the past five sessions.

Those declines came despite climbs at Chevron CVX and BP BP, which both reported higher profits this week on the back of the oil boom, and for the week were up 2.8% and 4.4%, respectively.

Exxon Mobil XOM was a notable exception, sliding 3.1% since Monday after failing to hit analyst estimates for the first quarter, despite a surging bottom line.

As for gold, the Market Vectors Gold Miners ETF GDX slid 4.7% for the week, while the iShares COMEX Gold Trust IAU and the streetTRACKS Gold Shares GLD fund each dropped 3.1%.