Analyst Upgrades

• Citigroup (C) to outperform from market perform at Bernstein.
• Cubist Pharma (CBST) to outperform from neutral at RW Baird.
• Pentair (PNR) to buy from hold at Citigroup.
• Heritage Financial (HFWA) to outperform from market perform at Keefe Bruyette.
• SL Green Realty (SLG) and Digital Realty (DLR) to market perform from underperform at FBR Capital.
• MGM Resorts (MGM) to neutral from Sell at Janney Capital.
• Ciena (CIEN) to buy from neutral and Olin (OLN) to buy from underperform at BofA/Merrill.
• Mellanox (MLNX) to overweight from equal weight at Barclays.
• ConocoPhillips (COP) and Canadian Natural (CNQ) to overweight from neutral at JPMorgan.
• IDEX (IEX) to outperform from perform at Oppenheimer.
• Taiwan Semiconductor (TSM) to buy from hold at Deutsche Bank.
• Ctrip.com (CTRP) to positive from neutral at Susquehanna.
• Linear Technology (LLTC) and Analog Devices (ADI) to hold from sell at Auriga.
• Quicksilver (KWK) to outperform from market perform at BMO Capital.

Here are a few highlights of this past week's earnings coverage from BloggingStocks:

• Alcoa Inc. (NYSE: AA) will kick off the new earnings season next week, but expectations are low.
• Bed Bath & Beyond Inc. (NASDAQ: BBBY) met low earnings estimates but shares dropped to a new low.
• Cal-Maine Foods' (NYSE: CALM) revenue and profit soared on strength in the market for fresh eggs.
• Merge Technologies Inc. (NASDAQ: MRGE) announced another dismal quarter, along with an SEC probe.
• Monsanto Co. (NYSE: MON) beat earnings expectations and revised its guidance.
• Retalix Ltd. (NASDAQ: RTLX) warned that it would miss earnings estimates again this quarter.

Also, Jim Cramer thinks that downgrades of tech stocks don't make sense in light of their strong fourth quarter, but analysts seem to be pessimistic in general about earnings forecasts. Ted Allrich thinks this is the wrong time to ignore financial stocks, despite recent losses.

Upcoming results to watch for include Alcoa Inc. (NYSE: AA) and KB Home (NYSE: KBH).

Visit AOL Money & Finance for more earnings coverage.

For investors, the hardest question often faced is when to sell a stock. Even when a stock issues a profit warning, if you are a long-term investor, that doesn't always justify one to pull the trigger.

There is no question it's easier to buy a stock than to sell. With that being said, today I was faced with an easy call. I call it the "three strikes and you are out" policy. If a company disappoints me three times in the span of six months, you're out (How long until pitchers and catchers report to spring training?).

Retalix (NASDAQ: RTLX) the Israeli provider of software solutions to retailers and distributors, today announced that it was going to miss its earnings estimates for the quarter. This is not the first time this has happened -- last quarter the same thing happened.