Midday Movers: HPQ, MRO & More

Take a look at some of Monday's midday movers:

Hewlett-Packard jumped amid unconfirmed reports that activist investor Carl Icahn may have an interest in the company.

Marathon Oil slid following news that its chief operating officer, David Roberts is stepping down.

Gap also fell on heavy volume, no news.

Marathon Petroleum traded near its best levels since its spin-off from Marathon Oil in June, 2011, after the oil refining company was named to Barron's list of 10 favorite stocks for 2013.

Kellogg traded near a 52-week high.

Citigroup fell after the banking giant increased the size of its debt buyback offer to nearly $1.2 billion.

Meanwhile, Dow component Johnson & Johnson edged higher after the drugmaker was upgraded to "buy" from "neutral" at Davenport with a price target of $80 per share.

(Read More: See CNBC's Market Insider Blog)

—By CNBC's Lori Spechler

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