The top after-market NYSE gainers Thursday were Mas Tec, LinkedIn Corp, Kodiak Oil, Sunoco and American Water Works Co. The top after-market NYSE losers were Knight Capital Group, Molycorp, Dolby Laboratories, Kayne Anderson MLP Investment and Active Network, Inc.

Gainers

Mas Tec, Inc. (MTZ) shares rallied 9.51 percent to $17.50 in post-market trading after raising its full-year earnings forecast. The company currently expects that the fiscal 2012 net profit will be $1.50 per share on revenues of $3.55 to $3.60 billion, up from its prior estimate of $1.42 per share on revenues of $3.35 billion and also topped analysts' estimate of $1.42 per share on $3.40 billion revenue.

LinkedIn Corp. (LNKD) shares climbed 7.31 percent to $100.35 in post-market trading. The company reported the second quarter adjusted net profit of $0.16 per share in line with analysts' estimate. Revenues for the quarter surged to $228.2 million from $121.0 million in the same period last year and also topped analysts' estimate of $215.73 million.

Kodiak Oil & Gas Corp. (KOG) shares surged 6.48 percent to $8.05 in post-market trading. Its second quarter net profit surged to $93.1 million or $0.35 per share from $14.0 million or $0.08 per share in the same period last year.

Sunoco, Inc. (SUN) shares surged 5.55 percent to $50.00 in post-market trading. The company swung to the second quarter net profit of $248 million or $2.35 per share compared to a net loss of $125 million or $1.03 per share in the same period a year ago.

American Water Works Co., Inc. (AWK) shares surged 4.72 percent to $37.96 in post-market trading. The company reported the second quarter net income of $107.03 million or $0.60 per share, up from $81.11 million or $0.46 per share in the same period last year.

Losers

Knight Capital Group, Inc. (KCG) shares slumped 13.95 percent to $2.22 in post-market trading. The company stock was downgraded to "sell" rating from a "buy" rating at CLSA.

Molycorp, Inc. (MCP) shares slumped 10.39 percent to $14.40 in post-market trading. The company swung to the second quarter net loss of $67.6 million or $0.71 per share compared to the net profit of $47.8 million or $0.53 per share in the same period last year.

Dolby Laboratories, Inc. (DLB) shares plunged 7.82 percent to $33.00 in post-market trading. Its third quarter net profit declined to $51.53 million or $0.48 per share from $61.75 million or $0.55 per share in the same period last year. Dolby lowered its fiscal 2012 adjusted net profit to a range of $2.75 to $2.83 per share from its prior estimate of $2.80 to $3.04 per share.

Kayne Anderson MLP Investment Co. (KYN) shares plunged 5.54 percent to $29.48 in post-market trading. The company announced Thursday that it had commenced a public offering of 5,000,000 shares of its common stock.

Active Network, Inc. (ACTV) shares plunged 5.02 percent to $13.25 in post-market trading. The company swung to the second quarter net loss of $0.04 per share compared to the net profit of $0.03 per share in the same period last year.