比教授，单纯TA，多空也没啥区别，你如果做空都能成功，那么这些年做多不是可以更成功，你为什么总是想着空呢？

Some anecdotes I find interesting by observing the results 189 years between 1825 and 2013:

• The market had 134 positive years and 55 negative years (the market was up 71% of the time)
• 44% of the time the market finished the year between 0% and +20%
• 60% of the time the market finished the year between -10% and +20%
• Only 14% of the time (26 out of 189 years) did the market finish worse than -10%
• Only a mere 4.8% of the time (fewer than 1 in 20 years) did the market finish worse than -20%

So to put it another way (using the 189 years between 1825 and 2013 as our sample space), there is an 86% chance that the market finishes the year better than -10%. There is a 95% chance the market ends higher than -20%. And as I mentioned above, there is a 71% chance that the market ends any given year in positive territory.

One last observation: the market was 5 times more likely to be up 20% or more in a year (50 out of 189) than down 20% or more in a year (9 out of 189)!