Exchange-traded funds tracking homebuilders were among the top performers of Friday's session. Among homebuilder names, Standard Pacific ( SPF) was up 2.8%, Hovnanian ( HOV) was adding 2.3%, Beazer Homes ( BZH) was higher by 2.1%, and Toll Brothers ( TOL) was rising 1.3%. The iShares Dow Jones U.S. Home Construction ( ITB) ETF was recently up 1.4%, or 47 cents, to $34.49. The SPDR Homebuilders ( XHB) ETF was climbing 35 cents, or 1.1%, to $32.75. The Biotech HOLDRs ( BBH) ETF was also rising. Holding Amgen ( AMGN) was gaining 3.2%, and the Biotech HOLDRs was recently higher by $1.53, or 0.9%, to $179.80. Other biotech ETFs were gaining ground. The iShares Nasdaq Biotechnology ( IBB) ETF was up 1.3% to $78.42, the First Trust Amex Biotechnology Index ( FBT) was gaining 1.2% to $24.53, and the SPDR S&P Biotech Index ( XBI) was rising 1.1% to $49.73. Also among winners, the PowerShares Lux Nanotech ( PXN) ETF rose as holding Altair Nanotechnologies ( ALTI) jumped 6.4%. The ETF was recently up 11 cents, or 0.6%, to $17.36. On the flip side, bundled securities tracking the energy sector were among the worst performers of the day. The front-month May crude contract continued to ease a day after Iran's President Mahmoud Ahmadinejad freed 15 British sailors and marines the country captured last month in the Persian Gulf. Crude prices were recently losing 34 cents at $64.04 a barrel. The iPath Goldman Sachs Crude Oil Index ( OIL) ETF eased 0.8% to $37.98. The United States Oil ( USO) ETF was recently down 0.7% to $51.99.