The top after market NYSE gainers  Monday were: Higher One Holdings, Qihoo 360 Technology, CPI Corp, Sequans Communications and Frontline Ltd. The top after market NYSE Losers were: Nustar Energy, Mac-Gray Corp, Federal Signal, Armstrong World Industries and Cardinal Health.

Gainers:

Higher One Holdings, Inc. (NYSE:ONE) shares surged 4.7 percent to $20.05 in post market trading session. Higher One will replace National Retail Properties in the S&P SmallCap 600 index after the close of trading Wednesday.

Qihoo 360 Technology Co. Ltd. (NYSE:QIHU) shares gained 4.47 percent to $18.41 in aftermarket trading session. The company stock declined more than 3 percent in regular trading session after Citron Research reported a negative report on QIHU.

CPI Corp. (NYSE:CPY) shares advanced 3.69 percent to $5.26 in aftermarket trading session. The stock has a 52-week low of $4.67, a 52-week high of $31.00 and $35.79 million in market capitalization.

Sequans Communications S.A. (NYSE:SQNS) shares advanced 3.41 percent to $4.24 in post market trading session.

Frontline Ltd. (NYSE:FRO) shares advanced 3.11 percent to $3.65 in aftermarket trading session. The company announced that its Board of Directors approved a restructuring plan which sees the creation of an independently trading company called Frontline 2012 and the subsequent sale of some of Frontline's assets to the new entity.

Losers:

Nustar Energy L.P. (NYSE:NS) shares plunged 4.47 percent to $53.22 in post market trading session. The company announced that it plans to conduct an offering of 5,250,000 common units pursuant to an effective shelf registration statement previously filed with the Securities and Exchange Commission.

Mac-Gray Corp. (NYSE:TUC) shares declined 3.24 percent to $12.93 in aftermarket trading session. The stock has a 52-week low of $11.29, a 52-week high of $16.98 and $191.13 million in market capitalization.

Federal Signal Corp. (NYSE:FSS) shares declined 2.98 percent to $3.88 in aftermarket trading session. Neology has filed a motion for preliminary injunction against Federal Signaland related companies to immediately stop directly or indirectly making, using, selling or offering for sale, importing or exporting, all infringing RFID tags, readers, and systems or sub-system.

Armstrong World Industries Inc. (NYSE:AWI) shares declined 2.78 percent to $41.31 in aftermarket trading session. The company announced on Tuesday that it is increasing its wholesale prices on select products because of rising raw materials costs.

Cardinal Health, Inc. (NYSE:CAH) shares declined 2.68 percent to $40.88 in post market trading session.