The Internet Infrastructure HOLDRs ( IIH) exchange-traded fund was the best performer of Thursday's session, as the volatile software sector turned higher. Among the ETF's holdings, VeriSign ( VRSN) jumped 4.1%, Akamai Technologies ( AKAM) was up 2% and BEA Systems ( BEAS) was rising 1.7%. The ETF was gaining 16 cents, or 2.9%, to $5.73. ETFs tracking silver and gold were also among the winners, as silver futures rose by 24 cents to $12.57 an ounce and gold futures gained $7 to $651.80 an ounce. The PowerShares DB Silver ( DBS) ETF was higher by 44 cents, or 1.8%, to $24.61. The iShares Silver Trust ( SLV) was up $1.66, or 1.4%, to $123.76. The PowerShares DB Gold ( DGL) added 35 cents, or 1.4%, to $25.76. On the other hand, housing-related ETFs were among the worst losers of the day. Earlier, KB Homes ( KBH) said it swung to a second-quarter loss due to lower demand and dwindling home prices. Among other housing concerns, Beazer Homes ( BZH) was losing 7.8%, DR Horton ( DHI) was down 1.6%, Centex ( CTX) eased 1.7% and Lennar ( LEN) was lower by 1.6%. The iShares Dow Jones U.S. Home Construction ( ITB) was recently falling by 51 cents, or 1.5%, at $31.83. The SPDR Homebuilders ( XHB) was down 39 cents, or 1.2%, to $30.93. The United States Natural Gas ( UNG) ETF was also slumping, due to a larger-than-expected build in natural gas inventories. Earlier, the Energy Department said that natural gas supplies rose by 99 billion cubic feet last week, sending natural gas lower by 5.3% to $6.71, a two-year low. The United States Natural Gas ETF was losing $2.45, or 5%, to $43.