Earnings season brings on a flurry of upgrades and downgrades, and it can be an all-day affair just to get through them all. Today we look at two telecoms, a component manufacturer, and a credit card payment servicer. Should you pay attention to Wall Street's call on them?

Company

Rating

Market Reaction as of 1 p.m. EDT
Time Warner Telecom (NYSE: TWTC) Upgraded from perform to outperform Up more than 3%
US Cellular (NYSE: USM) Upgraded from sell to neutral Up more than 3%
Visa (NYSE: V) Reiterated market perform with $145 price target Down more than 3%
Curtiss-Wright (NYSE: CW) Downgraded from buy to hold Down more than 3.2%

Source: Wall Street Journal Market Data Center.

Time Warner Telecom
Oppenheimer upgraded Time Warner Telecom from perform to outperform.

  • Why? The telecom company delivered overall strong results, meeting expectations on revenue and exceeding them on earnings per share due to improving margins.
  • Justified? No. While Time Warner Telecom is no doubt a strong performer in the industry, it is currently a bit rich in valuation, trading near its 52-week high and at more than 30 times forward earnings. Competitor AT&T (NYSE: T), also trading near its 52-week high, is much cheaper at only 13 times forward earnings. The company will benefit at year-end from an upcoming iPhone release.

US Cellular
National Securities upgraded US Cellular from sell to neutral.

  • Why? The upgrade was in hopes that tomorrow's earnings will beat analyst estimates. US Cellular recently entered into an agreement to operate in 500 Wal-Mart stores offering prepaid cellular services, which should give the company a nice boost.
  • Justified? No. While tomorrow's earnings release should give investors a clearer picture of the current state of the company, roller-coaster earnings over the last couple of years make this stock a little too difficult to predict.

Visa
FBR Capital holds a market perform rating on Visa and raised its price target to $145.

  • Why? Though the company's recent earnings release was about on par with expectations, Visa issued guidance of low double-digit revenue growth for 2012.
  • Justified? Yes. Visa has been a great performer over the long run. If you had the cash in 2009, you could have bought Visa for a ridiculous $40 per share. The stock has appreciated many times over since then and will continue to rise as the company benefits from a recovering economy.

Curtiss-Wright
Capstone Investments downgraded Curtiss-Wright from buy to hold.

  • Why? Curtiss-Wright met expectations but did not overly impress Capstone on forward guidance.
  • Justified? No. At a relatively inexpensive valuation compared to a competitor such as Honeywell, Curtiss should be a good performer over the next couple of years. The company guided double-digit revenue growth for the year. Government cuts in defense spending are a concern for Curtiss, though it is well diversified and should be able to adjust smoothly.

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.