Take a look at some of Monday's midday movers:
Call it the Twitter effect? Social media stocks are higher after Twitter announced an $80 million investment from BlackRock that values the social media company at $9 billion.
PetSmart shares were hit by a downgrade from Nomura to "reduce" from "neutral." The price target was also cut to $55 from $72. Nomura turned bearish on the pet supply retailer, saying its online advantage is being eroded by competitors including Amazon.com.
Hess was higher after announcing plans to exit the oil refining business and focus on exploration & production. In addition, activist hedge fund Elliot Associates filed with regulatory authorities to up its stake in shares of the energy company.
Waste Management and Republic Services traded up to 52-week highs after a Credit Suisse analyst noted both firms could qualify for conversion to REITs. Price targets were raised to $38 for both waste management companies.
Newmont Mining is trading down to its lowest price in a year.
Netflix shares hit a fresh 52-week high before reversing course and moving lower. The video streaming company has been on a tear since reporting its quarterly earnings, with shares up about 69 percent over the past week.
Lockheed Martin shares were lower after a Reuters report said it was a manufacturing problem that likely caused engine problems in its F-35B fighter jet.
(Read More: See CNBC's Market Insider Blog)
—By CNBC's Lori Spechler
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