Lesson 5: When to Sell
Because “don’t panic sell” isn’t a plan.
Objective
By the end of this lesson, you’ll be able to:
- Tell a good reason to sell from a bad one.
- Use rebalancing, stop-losses, and selling in pieces without overthinking it.
- Factor taxes into the timing of a sale.
- Write a sell plan for anything you own, before you need it.
Introduction
The Half of Investing Nobody Teaches
Everyone teaches buying. Buying is exciting. Selling is where plans quietly fall apart: people hold losers hoping they’ll come back, dump winners the moment they dip, and never actually collect the money they were investing for.
You’ve heard “don’t panic sell” a dozen times in this course. True, but not a plan. This lesson is the plan.
Main Content
1. Good Reasons to Sell
- You reached the goal. You invested for a down payment, and it’s time to buy the house. Selling is the point. Congratulations.
- Your reason for buying is gone. You bought Duck Co. because it dominated pond snacks. A competitor just ate its market share and earnings are falling (you can see it in the report from Lesson 1). The thesis broke. Sell, even at a loss.
- Rebalancing. One stock did so well it’s now 40% of your portfolio. That’s a lot of eggs in one basket. Trim it back to your target and spread the money around. This is the one time “it went up a lot” is a reason to sell.
- A clearly better use. A different investment offers more for the same risk, or you need the cash for something more important than the investment.
- Tax-loss harvesting. Selling a loser to offset gains elsewhere, as covered in Unit 4. Just mind the wash-sale rule: if you buy the same investment back within 30 days, the loss doesn’t count.
2. Bad Reasons to Sell
- The price fell. On its own, a drop tells you nothing about the business. Ask whether the thesis changed. If it didn’t, a lower price is a discount, not a signal.
- The price rose. Also on its own. “Taking profits” sounds wise but often means selling your best idea early. Sell because of rebalancing or a broken thesis, not because a number got bigger.
- A scary headline. Markets digest headlines in minutes. By the time you react, the move has happened.
- Boredom. A stock that does nothing for a year is not a problem. Doing nothing is most of investing.
- Someone online said so. See Lesson 4.
3. Tools That Take the Emotion Out
- Stop-loss order: an order to sell automatically if the price falls to a level you set (Unit 3, Lesson 1). Useful for short-term trades. Less useful for long-term holdings, where a normal dip can kick you out of a good investment.
- Trailing stop: a stop-loss that rises as the price rises, locking in gains while leaving room to run.
- Selling in pieces: can’t decide? Sell a third now, a third later, a third after that. You’ll never sell at the perfect price, and you’ll never sell everything at the worst one.
- Calendar rebalancing: pick a date (once a quarter, or once a year) and only trim positions then. It turns “should I sell?” into a scheduled chore instead of a daily temptation.
4. Taxes Have a Vote
From Unit 4: profits on investments held over a year are taxed at the lower long-term rate. If you’re a few weeks short of the one-year mark and the thesis is still fine, waiting can save real money. In a retirement account, none of this applies and you can sell freely. Taxes should shape timing, but they shouldn’t keep you in a broken investment. Paying tax on a gain beats watching the gain disappear.
5. Write the Exit Before You Buy
The best time to decide when you’ll sell is before you own the thing, while you’re calm. One paragraph is enough:
I’m buying Duck Co. because it leads pond snacks and grows earnings 15% a year. I’ll sell if earnings growth falls below 5% for two quarters, if it grows past 20% of my portfolio, or when I need the money for the house in 2031. I will not sell because the price dropped.
When the price does drop (it will), you read the paragraph instead of your feelings.
6. Letting Winners Run
The stocks that make a portfolio tend to be a few big winners held for a long time. Selling them early because they “went up a lot” is the most expensive mistake patient investors make. Rebalance when a position gets dangerously large, but otherwise, let a good business keep compounding.
Activity: Write Your Sell Plan
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Pick one investment you own, or one you’re planning to buy.
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Write one sentence on why you own it.
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Write the specific conditions that would make you sell: a goal, a broken thesis, a portfolio percentage, or a date.
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Write one sentence on what will not make you sell.
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Save it somewhere you’ll find it on a bad market day.
Reflection Question: If the price fell 25% tomorrow with no news, what does your plan say?
Summary
Sell when you reach your goal, when the reason you bought is gone, when a position grows too large, or when a loss can offset a gain. Don’t sell because the price moved, a headline scared you, or a stranger told you to. Use rebalancing, stops, and selling in pieces to keep emotion out of it, mind the one-year tax line, and write your exit before you buy.
Key Takeaways:
- Good reasons: goal reached, thesis broken, rebalancing, better use, tax-loss harvesting.
- Bad reasons: price fell, price rose, headlines, boredom, hype.
- Rebalance on a schedule, and consider selling in pieces when you’re unsure.
- Holding past one year lowers the tax rate, but don’t stay in a broken investment to save on taxes.
- Decide your sell rules before you buy, and let winners run.
Quiz Time!
Closing Thoughts
That’s the whole course. Five units, from “what is a stock?” to reading earnings reports, valuing a company, keeping the boring parts of your portfolio boring, dodging the foxes, and knowing when to let go.
You now know more than most people who invest. The rest is practice, patience, and the occasional deep breath. Keep learning, keep your plan where you can find it, and keep quacking.