Houston Wire & Cable ( HWCC) surged after the company said second-quarter sales increased 80% to $84.2 million. The company earned $8.3 million, or 48 cents a share, up from $2.2 million, or 13 cents a share, last year. Shares climbed $1.99, or 11.1%, to $19.97. Aftermarket Technology ( ATAC) gained after the engineering services company was upgraded by UBS to buy from neutral. Shares gained $1, or 4.9%, to $21.43. Commercial Vehicle Group ( CVGI), an auto-parts company, jumped following an upgrade by Robert W. Baird to outperform from neutral. Shares climbed $1.44, or 8.3%, to $18.84. CV Therapeutics ( CVTX) dropped after the biopharmaceutical company said it's selling 7.5 million shares in a public offering. The company granted the underwriters an option to purchase up to an additional 1.13 million shares to cover overallotments. Shares fell 82 cents, or 7.6%, to $10.03. Double Hull Tankers ( DHT) slipped after the company was downgraded by Citigroup to hold from buy. Shares dropped 46 cents, or 3.1%, to $14.37.