When to actually sell — the exit math nobody teaches

I'm Michael Rupert. I'm not a guru. I'm a quantitative analyst, a mathematician. I have a bachelor's degree in mathematics, a master's degree in data science, and have completed doctoral coursework in computational mathematics. I built Olympia because I wanted a tool that strips the emotion out of trading and focuses instead on logic and historical probability.

Today's lesson is the one almost nobody teaches: when do you actually sell and exit a trade? Everyone teaches the buy. Almost nobody teaches the sell — and the sell is where accounts actually die. This one is Apple, AAPL, a swing trade, start to finish. By the end you'll see the whole exit plan, and the whole point is that every line was decided before the trade was on. Not in the heat of the moment — in advance. Getting in is easy, but knowing when to get out is everything.

Quick vocabulary before we dive in. You don't have to memorize these; I'll explain each one again as it comes up. The capital letter R just means your risk. Reward to risk is what you're trying to make versus what you're willing to risk. ATR is average true range — a stock's normal daily wiggle from high to low. Support is a floor: a level where price bottomed out in the past. Resistance is the ceiling: the upper limit, the highest it's gone in the past. That's the whole vocabulary. No jargon walls.

So here's the entry: 284. This is exactly where most people stop planning. They buy, then they say, “Let's see what happens.” That's not a plan. That's a hope with money attached to it. A trade with no preset exit isn't a trade. So let's build the plan, starting with the number that caps your downside.

There are multiple exits. The first is the stop. We set the stop at 274 — the most I'm willing to lose on this trade, decided up front. From 284 down to 274, I only want to lose $10 a share. R is $10. One unit of risk, for me, is $10, and R is the ruler we use to measure the whole trade.

The magic isn't the number, it's the timing. I picked my worst case while I was calm. I'm not doing it later. I'm not doing it while I'm bleeding. I'm setting the stop now, not out of fear, and I'm done. That's my stop. That's what I'm willing to lose.

Now you might be thinking, “Mike, why 274? Why not some other random number?” It's a fair question, and here's the honest answer at three levels. If you're a beginning trader, put the stop just below support — the swing low where the stock already bounced, the floor where buyers stepped in before. If price breaks back under that floor, the whole reason you bought the stock is gone, and you're out. If you're a novice, the gap between entry and stop is your risk, one R — $10 here — and both your target and your position size get measured from it. If you're an advanced trader, size the buffer with volatility: ATR, the average amount a stock moves in a bar, its normal wiggle. Put the stop about one and a half times that below your entry, so the noise doesn't stop you out but a real break does. Bottom line: a stop isn't what you can afford to lose. It's the price that proves you wrong.

Now the trade's working. As price climbs, the first target sits at 304 — a reward-to-risk ratio of two to one, decided before I got into the trade. The second it's there at 304, I'm locked in at plus $20: plus two R, twice my risk.

How do I hold on to that gain? With a trailing stop — a stop that only goes up, never down, riding a set percentage below the price. Here's the catch most people miss: a trailing stop sits below the peak, so the stock has to climb a little past 304 for the stop to pull up to it. How far past depends on how tight you set the trail. With a 2% trail, the stock has to reach about 310; then a 2% dip pulls the stop up to 304 and locks the $20. A 3% trail has to hit about 313, and a 5% trail about 320. Tighter trails lock it in sooner but get shaken out by small wiggles. Wider trails let it run but give more back. Either way, the stop only ratchets up. It never gives ground.

The most painful thing in trading is watching a green winner bleed all the way back to a loss. A winner turning into a loser is a decision — and the trailing stop makes that decision for me, automatically.

The third exit is the target at 314: plus $30, three times my risk. There's the whole equation. I risked one R to make three — a 3:1 reward to risk — and I knew it before I ever clicked buy. Three exits, three jobs: the stop caps the loss, the trail protects the gain, the target books the win. None of them were done emotionally. All of them were math I wrote down in advance. And if you want the full three to one after the trail, you may need to aim a bit higher than 314, depending on the trail you choose.

So why 314? There are two honest ways to pick a target, and the best trades use both. If you're a beginner, aim just under the ceiling — resistance, the prior high or a round number where price tends to stall, where sellers stepped in before. Sell into strength instead of hoping it breaks through. If you're a novice, make it pay: target 3R, three times your $10 risk, which lands right at 314. Rule of thumb: skip anything paying less than about two to one. If you're advanced, when the math number and the real chart level line up, that's your best exit — or scale out: bank some at plus 2R and trail the rest for the big runners.

Here's the finished picture. Every line, every number, locked in before the trade went live. Entry 284. Stop 274, risking 1R. Trail to 304, locking 2R. Target 314, booking 3R. A clean 3:1 plan. And look at what's missing: no fear, no hope, no “let me just see what happens.” That absence is the entire edge. Everything else is noise.

This is the whole philosophy. You're not smarter than the market in the moment — nobody is. The moment is where fear and greed live. So you move the decision out of the moment. Decide all three exits before you're in. Price hits a line, you act. No debate. That's how you protect your capital and stay unemotional — not by being tough, but by having already decided.