Exchange-traded funds tracking financial stocks were among the worst performers this week as uncertainty abounded regarding impending first-quarter writedowns at the sector's biggest names.

At the end of the week, Ultra Financials ProShares ( UYG) had tanked 11.1%. The Financial Select SPDR ( XLF), Vanguard Financials ( VFH) and iShares Dow Jones U.S. Financial Sector ( IYF) lost 6.1% or more.

The week saw Oppenheimer predicting that Citigroup ( C), Merrill Lynch ( MER) and UBS ( UBS) will probably write off another large batch of soured assets and post losses for the first quarter. Further, speculation resurfaced that Lehman Brothers ( LEH) is suffering from liquidity troubles -- a suggestion the firm has fought back against.

ETFs tracking retail shares also lost ground as J.C. Penney ( JCP) ended the week by slashing its first-quarter earnings forecast, blaming soft consumer spending. Another blow came earlier this week when the Conference Board released dismal consumer-confidence numbers.

Over the past five sessions, Retail HOLDRs ( RTH) lost 2.7%, SPDR S&P Retail ( XRT) shed 4.6% and PowerShares Dynamic Retail ( PMR) surrendered 3%.

Bundled securities tracking energy and gold were among the week's few winners, however, as investors bulked up on crude and gold futures amid a weakening U.S. dollar.

Oil Services HOLDRs ( OIH) was one of the best performers, spiking 5.9% for the week. Ultra Oil & Gas ProShares ( DIG) added 2.6%, United States Oil ( USO) rose 3.5%, and Energy Select Sector SPDR ( XLE) tacked on 3.8%.

As for gold-related ETFs, since Monday the Market Vectors Gold Miners ETF ( GDX), PowerShares DB Gold ( DGL), iShares COMEX Gold Trust ( IAU) and streetTRACKS Gold Shares ( GLD) all climbed 2% or more.

More from ETFs

What Bad Weather? Kohl's Shares Spike as Same-Store Sales Jump

What Bad Weather? Kohl's Shares Spike as Same-Store Sales Jump

Listen: Here's What You Need To Know About ETFs Today (Hint: They're on Fire!)

Listen: Here's What You Need To Know About ETFs Today (Hint: They're on Fire!)

Bitcoin Today: Bears Rear Their Heads as Prices Continue Downward Spiral

Bitcoin Today: Bears Rear Their Heads as Prices Continue Downward Spiral

Cannabis Stocks Are Screaming Sells After Seeing This Deal: Doug Kass Insider

Cannabis Stocks Are Screaming Sells After Seeing This Deal: Doug Kass Insider

60 Seconds: What's the Difference Between an ETF and a Mutual Fund?

60 Seconds: What's the Difference Between an ETF and a Mutual Fund?