"The time to sell a stock is - almost never." The four rules of selling.

Philip Fisher, in his book Common Stocks and Uncommon Profits wrote, “If the job has been correctly done when a common stock is purchased, the time to sell it is—almost never.”

I sincerely believe in this idea of never selling my stocks, IF I did the job of picking them well. But then, there are times when you must sell your stocks, and one of the keys to investment nirvana is the ability to know when to do that. 

Four rules of Selling

A value investors in India, Sanjoy Bhattacharyya, wrote on the art of selling stocks some years back, wherein he shared the four rules of selling –

While remaining disciplined in terms of the process of stock-picking, the seasoned value investor waits patiently for Mr. Market to provide opportunity.

          
     Typically, there are just four reasons to sell:

1. A clear deterioration in either earning power or ‘asset’ value.
2. Market price exceeds ‘fair’ value by a meaningful margin.
3. The primary assumptions, or expected catalysts, identified prior to making the investment are unlikely to materialise or are proven to be flawed.
4. An opportunity likely to yield superior returns (with a high degree of certainty) as compared to the least attractive current holdings is on offer.

 https://www.safalniveshak.com/riskiest-moment-in-investing/