U.S. markets opened the first full week of 2014 trading to the upside but a duo of downgrades are weighing on two familiar names. Twitter shares are lower on the back of a downgrade from Morgan Stanley. Morgan Stanley says Google and Facebook are better positioned to take advantage of online ad spending. First Solar received a downgrade to "sell" from Goldman Sachs. Meantime Liberty Media is making a big to acquire the remainder of Sirius that it doesn't already own. And, Zynga says it will start accepting Bitcoin for some of its products.

More from Video

Sprout CEO: Don't Call Her Drug the Female Viagra

Sprout CEO: Don't Call Her Drug the Female Viagra

Futures Fall on Further Trade Rhetoric from China and 4 Other Stories to Watch

Futures Fall on Further Trade Rhetoric from China and 4 Other Stories to Watch

Jim Cramer's Investing Rule 15: Don't Forget About Bonds

Jim Cramer's Investing Rule 15: Don't Forget About Bonds

Immigration, Instagram and Oil - Here's What You Can't Miss Wednesday

Immigration, Instagram and Oil - Here's What You Can't Miss Wednesday

REPLAY: Jim Cramer on Fed Rate Hikes, Oil Prices and Starbucks Worries

REPLAY: Jim Cramer on Fed Rate Hikes, Oil Prices and Starbucks Worries