The top aftermarket NYSE gainers Thursday were: China Cord Blood Corp, Sandridge Energy, Unisys Corp, Overseas Shipholding Group, Dow Chemical, 3D Systems Corp, Sara Lee Corp, Venoco, Thompson Creek Metals and Renren Inc.

China Cord Blood Corp. (CO) shares surged 3.51 percent to $2.95 in aftermarket session. The company and Kohlberg Kravis Roberts & Co. announced that they have entered into agreements under which KKR China Growth Fund L.P. is expected to invest $65 million into China Cord Blood to support its further business expansion and to capitalize on China's fast growing healthcare services industry.

Sandridge Energy Inc. (SD) shares surged 3.38 percent to $7.80 in aftermarket session. The company stock surged more than 5 percent in regular session.

Unisys Corp. (UIS) shares surged 3.02 percent to $17.38 in post market session. The company announced that it will release its first-quarter 2012 financial results on Tuesday, April 24, 2012 after the close of trading on the New York Stock Exchange.

Overseas Shipholding Group, Inc. (OSG) shares gained 2.59 percent to $10.68 in aftermarket session. The company stock was upgraded to “neutral” rating from an “underperform” rating at Zacks Research.

Dow Chemical Co. (DOW) shares gained 2.51 percent to $33.49 in post market session after gaining more than 2 percent in regular trade. The company announced that its board boosted the company's second-quarter dividend by 28 percent to $0.32 per share.

3D Systems Corp. (DDD) shares advanced 2.5 percent to $25.00 in post market session after gaining more than 5 percent in regular trade. The stock has a 52-week low of $12.78, a 52-week high of $27.28 and $1.24 billion in market capitalization.

Sara Lee Corp. (SLE) shares rose 2.35 percent to $21.81 in post market session. The stock has a 52-week low of $15.66, a 52-week high of $22.04 and $12.61 billion in market capitalization.

Venoco, Inc. (VQ) shares gained 2.24 percent to $10.49 in aftermarket session. The company stock declined more than 2 percent in regular trading.

Thompson Creek Metals Co, Inc. (TC) shares rose 1.96 percent to $6.75 in post market session.

Renren Inc. (RENN) shares gained 1.60 percent to $6.97 in post market trading after surging more than 11 percent in regular trade.

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