Here is a question: How do you decide when to buy or sell a stock?I started trading in SGX a year ago, and every time I have money to invest, I always wonder “Should I buy now? But if not now, then when?” Since I didn’t have a good answer to that question, what I’ve been doing till now is simply buy the best stock that fits my portfolio whenever I have cash.

That was the best I could do then, but I believed there must be a better way to do this and have been thinking about it. One idea that recently took form is using short selling activities to identify a good entry point to buy.

To give a quick illustration of what short selling is, imagine that A borrows a book from B.
A then sells the book to C and gets cash on the …