Why I Avoid Earnings

Many people like to play around corporate earnings.  I think that's fine as a speculative strategy, but not as a reliable one.  Here are some examples of why I avoid earnings:

• Jan 16 2013 JPMorgan's net profit surges 54%. JPMorgan Chase's (JPM) Q4 net income jumped 54% to $5.7B as EPS of $1.39 beat consensus but a revenue increase of 10% to $24.4B missed forecasts. JPMorgan has also released internal reports about its $6.2B Whaling Loss. Shares were -0.2% premarket. 
• 28 Jan 2013 4:05 PM VMware (VMW): Q4 EPS of $0.81 beats by $0.03. Revenue of $1.29B (+22% Y/Y) in-line. Shares -5.8% AH.
• 6 Feb 2013 4:12 PM Visa (V): FQ1 EPS of $1.82 beats by $0.03. Revenue of $2.85B (+12% Y/Y) beats by $3M. Shares -0.1% AH.
• 31 Mar 2013 6:52 PM Micron Tech (MU), a chipmaker, said it lost 28 cents in Q2, worse than the expected 19-cent loss. Revenue was flat at $2 bil, slightly above. Shares rose 3.9%.
• 22 Apr 2013 7:34 AM Caterpillar Inc. (CAT): Q1 EPS of $1.31 misses by $0.07. Revenue of $13.2B (-17% Y/Y) beats by $600M. Shares +0.7% premarket.