Then after he read some book on WEB, he tried to invest massively by buying stocks. Now most of the time he sell covered calls or naked puts.
From what he said yesterday, half of puts of NTES were written by him. And he was joking that to see so many people working for him (by buying his puts) was fun.
应该什么时候卖股票
I think he gave you the answer. Hold it as long as you can unless the company has changed.
His opinion is just a standard one of value investor's. As WEB said, if you are going to do value investment, you are going to do it in 5 min. Duan became a value investor right after he read the book.
Duan did very very massive research on his stocks as ruskin has noticed from Duan's talk. He hired lawyers, accountants, game players, etc. and most importantly by himself.
But you do not need those methods to get a rough idea. That is why you buy something worth $1 for 50c. And you do not need any of those methods to buy if the price plunges. And you do not need any of those methods to hold your shares. For UHAL, he bought all the way from $5 to $3 and he was so happy to see the price dropping that he could buy more. When the price was up to $7 again after ch11 declaration, he never bought a share again.
我必须指出,截至目前我们所观察的记录,投资组合在整段期间都几乎没有重叠。他们都是根据价格与价值间的差异来选股,选择的标的也截然不同。华特的最重要持股都是扎实的企业,如Hudson Pulp&Paper、Jeddo HighHand Coal、 New York Trap Rock Company,即使是偶尔阅读金融版新闻的人,对这些企业的名称也耳熟能详。帝地布朗公司所选择的标的则更是名不见经传的企业。另一方面,比尔的选择标的则是大型企业。这些投资组合极少出现重叠现象。他们的记录并非由某人主导的猜测铜板,其他人则只听命附和。