When to sell

Kabir's grandmother planted a mango tree in their courtyard when Kabir was a baby. Every summer it gives sweeter and more plentiful mangoes. One day a neighbour offers to buy the tree for a good price. Another day a storm knocks off some leaves and Kabir panics, thinking the tree is dying. On yet another day, a man walks by and says mango trees are "boring" and Kabir should plant something new and exciting.

Kabir's grandmother just smiles at all of this. She does not dig up the tree because someone offers money for it. She does not dig it up because a storm scared her for one afternoon. She does not dig it up because a stranger called it boring. She would only remove the tree for a real reason - if it truly stopped giving good fruit, or if she discovered it was diseased, or if she found a far better tree to plant in its place. For everything else, she leaves it alone and lets it grow.

Philip Fisher thought about selling a share exactly like this. He said that if you have found a truly wonderful business, you should sell it almost never. Most reasons people sell - the price wobbled, the price went up a lot, someone said it was boring - are like the storm and the passing stranger. They are not real reasons at all. There were, for Fisher, only a very small number of real reasons to sell, and everything else was just noise trying to make you dig up your mango tree.

Fisher said there are really only three good reasons to sell a wonderful company. All three are about the business or your thinking - never about the day's price.

Real reason one: you made a mistake. When you look again, honestly, you realise the business was never as good as you first thought. You misjudged it. The bosses turned out to be dishonest, or the product was weaker than you believed. If your reason for buying was simply wrong, it is right to admit it and sell.

Real reason two: the business has truly gotten worse. The company was excellent, but something real has changed for the bad and looks likely to stay that way. Its products have fallen behind, its runway has run out, good bosses have left and careless ones taken over. Not a bad quarter - a lasting fall in the quality of the business itself.

Real reason three: you have found something clearly much better. You have discovered another business that is so obviously superior that moving your money there is worth it - and you should be strict, because "a bit better" is not enough. It must be clearly much better to justify pulling up a tree that is still growing well.

Look at the difference. The three real reasons are all about the business or your judgement. Every fake reason is about the price or your feelings. That is the whole trick to reading this. When you feel the urge to sell, ask one question: "Is the business worse, or did I just make a mistake, or have I found something clearly far better? Or is this only about the price moving and my nerves jumping?" If it is only the price and the nerves, Fisher would say: sit still. Do not dig up the tree.

The most tempting fake reason of all is "it went up a lot, so I should sell and take my profit." This feels wise, but Fisher warned it is often the biggest mistake of all. If the business is still wonderful and still growing down a long runway, selling it just because it rose means you throw away all the years of growth still to come. You cut down the mango tree right when it is about to give its biggest harvest. The whole reward of finding a great business comes from holding it while it grows - and you cannot hold it if you keep selling every time it does well.

illustrative Two friends, Neha and Rohan, each buy the same wonderful company for ₹1,00,000. It is an excellent business with a long runway, growing near 20% a year.

After three years, the value has risen to about ₹1,70,000. Neha feels nervous. "It went up so much - what if it falls? Let me take my profit." She sells for ₹1,70,000 and feels clever. She has earned ₹70,000. She then puts the money into three so-so shares that a friend suggested, none of them wonderful.

Rohan does nothing. He remembers Fisher's rule: the business is still excellent, still growing, so there is no real reason to sell. He simply holds. The company keeps flying down its runway. After ten years from the start, growing near 20% each year, Rohan's ₹1,00,000 has become roughly ₹6,00,000. Neha's ₹70,000 profit, spread across ordinary shares, grew far less.

Neha did nothing "wrong" in the everyday sense - she took a real profit. But she cut down the mango tree in year three and missed the seven years of biggest harvest. Rohan's patience, not any clever trade, was what turned a small sum into a large one. That is Fisher's whole point: with a truly wonderful business, the money is made by sitting still, and selling for a fake reason is how most people give that money away.

"Hold almost forever" only works if it is truly wonderful. This rule was made for the rare, excellent, long-growing business. If you apply "never sell" to an ordinary or weak company, you are not being patient - you are being stubborn, and you may ride it all the way down. The rule protects great trees; it does not order you to keep a dying one.

Refusing to sell can become refusing to admit a mistake. The hardest sell is the honest one: realising the business has truly gotten worse, or that you were wrong to begin with. It is painfully easy to pretend nothing has changed just to avoid the pain of admitting error, and call your stubbornness "patience." Real patience keeps a still-great business; it does not cling to one that has genuinely broken. Be honest about which is which.

Telling "truly worse" from "just a bad patch" is hard. Every good business has bad months and scary headlines. The skill is separating a lasting fall in quality from ordinary bumps - and that is genuinely difficult. Sell too quickly at every bump and you lose the reward of holding; sell too slowly when the business is really breaking and you ride it down. There is no easy formula, only careful, honest judgement.

The heart of this idea - do not sell a wonderful, growing business for a fake reason - is useful anywhere, and it protects you from your own nerves. In our markets, prices jump around a lot and news is loud and full of scary or exciting stories every single day. That noise pushes people to trade far too often, buying and selling on feelings and cutting down their trees again and again. Fisher's rule is a calm anchor against that noise: judge the business, not the daily price.

But use it wisely, not blindly. "Hold forever" is not a law of nature - it works only for genuinely excellent businesses, and only as long as they stay excellent. You still have to keep reading the company honestly, and be brave enough to sell when it has truly broken or when you have truly made a mistake. Fisher's honest lesson is this: with a rare, wonderful business, patience is what pays - so sell only for a real reason about the business or your judgement, never because the price moved or your nerves jumped, while staying honest enough to admit when a tree really has stopped bearing fruit. Which case you are in is always your own careful judgement to make.

• Before selling, name the real reason. Is the business worse, did you make a mistake, or have you found something clearly far better? If not, sit still.
• Never sell just because the price went up. Selling a wonderful, growing business to "take profit" often means giving away its biggest years.
• Ignore the daily wobbles and scary headlines. These are storms passing over the tree, not reasons to dig it up.
• Be honest about mistakes. If the business was never as good as you thought, admit it and sell - do not dress up stubbornness as patience.
• Watch for a real, lasting fall. A worse product, an empty runway, or careless new bosses are real reasons; a single bad quarter is not.
• Demand "clearly much better," not "a bit better." Only a plainly superior business is worth pulling up a tree that is still growing well.