Herbalife Puts More Pressure on Ackman And Other #Stocks2Watch

#Stocks2Watch: FOX Business rounds up the stocks you should watch before the opening bell rings on Wall Street. Tweet @adamsamson or e-mail adam.samson@foxbusiness.com and tell us what stocks you're watching -- your picks could appear online!

1. Herbalife [HLF]

Herbalife revealed adjusted fourth-quarter profit estimates that topped analysts' expectations, and increased the size of its stock buyback program to $1.5 billion from $1 billion. The shares are rallying more than 2% in pre-market action. The rising shares put pressure on hedge fund heavyweight Bill Ackman, who has a $1 billion short position on the nutritional-product supplier on the thesis the firm is a pyramid scheme. Herbalife has repeatedly denied those allegations.

2. Zynga [ZNGA]

Zynga was downgraded to "underweight" by analysts at Bank of America Merill Lynch, according to a report by Reuters. The social game-maker unveiled a restructuring plan last week that includes slashing 15% of its workforce. The shares are down 2% in pre-market action, but are up close to 16% for the year.

3. Vodafone [VOD]

Vodafone shares are down 1.5% in the pre-market. It's not immediately clear what's driving the action, but there has been talk recently that AT&T is considering a buyout of the European telecommunications giant.

4. Automakers [F | GM | FIATY]

The Big Three U.S. automakers, Ford, General Motors and Fiat's Chrysler are set to post monthly sales figures on the day. The monthly data are seen as leading indicators of consumer sentiment and retail sales.

5. Yum Brands [YUM]

Yum Brands, the owner of KFC and Taco Bell, is set to report its quarterly earnings after the closing bell. The shares have fall slid about 11% for the year.