The top aftermarket NYSE losers on Monday were: Vulcan Materials, Skilled Healthcare Group, IntraLinks Holdings, Sun Life Financial, MarkWest Energy Partners, Mechel Steel Group OAO, Gildan Activewear, Frontline and Mueller Water Products.

Vulcan Materials Co. (NYSE:VMC) shares slumped 7.66 percent to $38.60 in post market trading session. Glancy Binkow & Goldberg LLP announces that it is investigating potential claims against the board of directors of VMC concerning an unsolicited offer to acquire the Company by Martin Marietta Materials Inc. in a deal valuing Vulcan stock at $4.7 billion.

Skilled Healthcare Group, Inc. (NYSE:SKH) shares plunged 6.35 percent to $4.87 in aftermarket trading session. The stock has a 52-week low of $3.30, a 52-week high of $15.93 and $197.67 million in market capitalization.

IntraLinks Holdings, Inc. (NYSE:IL) shares declined 5.06 percent to $6.00 in post market trading session.

Sun Life Financial Inc. (NYSE:SLF) shares declined 3.58 percent to $18.68 in aftermarket trading session. The company stock surged more than 6 percent in regular trading session.

MarkWest Energy Partners, LP (NYSE:MWE) shares declined 3.31 percent to $54.25 in aftermarket trading session. The company announced that it plans to buy the remaining 49 percent in its MarkWest Liberty joint venture from Energy & Minerals Group for $1 billion in cash and the issuance of 19.95 million unregistered MWE Class B Units to EMG.

Mechel Steel Group OAO (NYSE:MTL) shares declined 3.31 percent to $54.25 in post market trading session.

Gildan Activewear, Inc. (NYSE:GIL) shares declined 2.8 percent to $18.87 in post market trading session. The stock has a 52-week low of $16.32, a 52-week high of $38.07 and $2.36 billion in market capitalization.

Frontline Ltd. (NYSE:FRO) shares declined 2.36 percent to $3.31 in post market trading after plunging more than 6 percent in regular trading session.

Mueller Water Products, Inc. (NYSE:MWA) shares declined 2.34 percent to $2.09 in aftermarket trading session.

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