Earnings season brings on a fury of upgrades and downgrades, and it can be an all-day affair just to get through them all. Today we look at a tobacco company, a memory storage manufacturer, a mobile gamer, and a commercial real estate services firm. Should you pay attention to Wall Street's call?

Company

Rating

Reaction as of 1 p.m. EST

Philip Morris International (NYSE: PM) Reiterated buy Up more than 2%
SanDisk (Nasdaq: SNDK) Upgraded to buy from neutral Up more than 1%
Zynga (Nasdaq: ZNGA) Upgraded to overweight from equal weight Down more than 5%
CBRE (NYSE: CBG) Named bull stock of the day and upgraded to outperform from neutral Unchanged

Source: Street Insider, Zachs, Wall Street Cheat Sheet.

Philip Morris International
Argus issued a reiterated buy rating on Philip Morris with a raised price target from $88 to $94.

  • Why? Argus was impressed by fourth-quarter earnings. Renewed demand in Europe and growing Asian operations are the company's main growth drivers.
  • Justified? Yes. With a nice dividend yield and rising profits, Philip Morris looks to be adjusting well to the less favorable U.S. market by focusing on international prospects. Investors are excited as the company is busting through its 52-week high.  

SanDisk
Jeffries upgraded SanDisk to buy from neutral.

  • Why? Diverse product offerings, improving pricing conditions, and low downside risk are the main reasons Jeffries bumped the memory storage company up to a buy rating.
  • Justified? No. The downside risk argument is the strongest point Jeffries makes as the company has $15 per share in cash alone -- nearly 50% of today's share price. SanDisk faces an industry overhaul as many tech companies are focusing on cloud storage as the future of the business. Physical flash drives are still necessary today, but this business does not have a wide moat in the future. Seagate (Nasdaq: STX) is a more interesting play in this space, trading dirt cheap and having just initiated a $2.5 billion stock repurchase program.

Zynga
JPMorgan upgraded Zynga to overweight from equal weight.

  • Why? While earnings were overall weak, analysts were impressed by the growth of the mobile business -- which they can consider to still be in its infancy. Recurring revenue streams from Zynga's poker segment are also encouraging.
  • Justified? No. Zynga is undoubtedly an industry leader in the mobile gaming business, but declining sales and the short life span of its hit games make this a tough business to predict. Different from traditional console games, Zynga's products tend to skyrocket in popularity, only to fizzle out a few months down the road. The company is also not shareholder friendly.

CBRE Group
Zacks named CBRE its bull stock of the day and upgraded the stock to outperform from neutral.

  • Why? Zacks likes the commercial real estate firm based on its strong earnings compared to competitors, diversified properties, and long-term outlook.
  • Justified? Yes. Though it looks expensive at 26 times TTM earnings, the company is trading at under 13 times its forward-looking earnings. Year-over-year revenue growth was not too impressive, but net income from continuing operations made a strong gain over last year. CBRE is poised to benefit from improving commercial real estate conditions in many parts of the United States.

Ratings are often based on short-term prospects and not relevant to the long-term investor. However, we can use these to dig up useful facts about a company we may not have seen before. It's important not to let the ratings themselves color your opinion of a company. As Fools often say -- better to do the research yourself and come to your own conclusions. Keep an eye on this series to stay in the know and save the rest of your day for coffee and Facebook.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.