What it is

A position's health is an ongoing assessment of whether an open trade still deserves your capital, and an exit strategy is the pre-defined set of rules that decides when and how you leave. Most traders obsess over entries, but the entry only opens the trade - the exit is what converts it into a realised gain or loss. Two traders can take the identical entry and walk away with completely different outcomes purely because of how they manage the exit.

Exit decisions fall into three families: cutting a loser before it grows (the stop-loss order), protecting and harvesting an open profit (the trailing stop and scaling out), and leaving for reasons unrelated to price (the thesis broke, time ran out, a better opportunity appeared). A complete strategy specifies all three in advance, so that the noisiest, most emotional part of trading is governed by rules written when you were calm.

How it works

Trailing stops. A trailing stop is a stop order that follows price by a fixed distance as the trade moves in your favour, but never moves against you. If you buy at 100 with a trailing stop 8 below, the stop rides up to 102 when price reaches 110, to 107 when price reaches 115, and so on - locking in more of the open profit at each new high. The distance is usually set in a way that respects the instrument's volatility: a common method is a multiple of ATR (Average True Range), so a noisy stock gets more room and a quiet one gets less. The trade-off is direct: a tight trail captures more of a peak but is easily shaken out by normal noise; a wide trail survives the noise but gives back more before exiting.

Scaling out. Instead of closing the whole position at once, scaling out sells it in tranches as price hits successive targets - for example, a third at the first target, a third at the second, and letting the final third run behind a trailing stop. This deliberately trades some upside for a smoother equity curve and lower regret: you bank gains early enough to avoid round-tripping a winner, while keeping a runner in case the move extends. It is the practical compromise between "sell too early" and "hold too long."

Exit rules. Beyond price-based exits, healthy positions need rules for the reasons price cannot capture. A thesis-based exit closes the trade when the original reason for it is invalidated - an earnings miss, a broken trend, a failed breakout - even if the stop has not been hit. A time-based exit closes a trade that has gone nowhere after a set period, freeing capital and attention. These rules matter because a position that is no longer working but has not yet hit its stop is the most expensive kind of dead weight.

How to use it

Build your exit plan at the same moment you build your entry, and write it down so it survives contact with a live, moving market:

1. Set the initial stop from risk, not hope. Place the stop where the trade idea is objectively wrong, then size the position so that distance equals your fixed risk per trade. The stop defines the trade; the size follows from it.
2. Choose how the stop will move. Decide in advance whether the stop is static, moves to breakeven after a defined gain, or trails by an ATR multiple. Do not invent this rule mid-trade.
3. Define profit-taking before you are in profit. Write your scale-out levels and the size sold at each, plus what happens to the runner. Decisions about taking profit are far cleaner made before the dopamine of an open gain arrives.
4. List the non-price exits. State explicitly what would invalidate the thesis and the maximum time you will hold a flat trade.
5. Never widen a stop. Tightening or trailing a stop in your favour is management; moving it away to avoid being stopped out is just turning a small planned loss into a large unplanned one.

Worked example

You buy 300 shares at $50, with an initial stop at $46 - a $4, or 8%, risk, which equals your planned 1% account risk on this trade. You set two profit targets at $58 and $64, planning to sell 100 shares at each, and to trail the final 100 behind a 2x ATR stop. Price reaches $58: you sell 100 and move the stop on the rest up to breakeven at $50, so the trade can no longer lose money. Price reaches $64: you sell another 100, banking a second tranche. The last 100 ride a trailing stop that has climbed to $60; price peaks at $70, rolls over, and you are stopped out at $60. You captured a clean gain on two thirds at fixed targets and a larger gain on the runner - without needing to predict the exact top, and without ever risking more than your planned 1%.

Strengths & limits

Disciplined exit management is what makes a positive expectancy survive contact with reality. Trailing stops let profits run while defining the most you will give back; scaling out reduces the emotional whipsaw that pushes traders to sell winners too early or hold them too long; and written exit rules remove the in-the-moment improvisation that quietly destroys edges. Together they ensure your average loss stays small and your average win is allowed to grow - the core of a durable risk-reward ratio.

The limits are equally important to internalise. A trailing stop set too tight in a volatile name will repeatedly stop you out just before the move resumes; set too wide, it surrenders a painful slice of profit. Scaling out caps your upside on the trades that run furthest - over a sample, your biggest winners would have been bigger had you held - so it is a deliberate trade of expected return for smoother, more repeatable results. And no exit framework helps if you override it: the failure mode is almost never the rule, it is the trader who widens a stop "just this once." Slippage and gaps mean a stop is a plan, not a guarantee of the exact fill price, especially around news.

Key takeaway: Exits decide returns - use trailing stops to lock in gains while letting winners run, scale out to trade some upside for smoother results, and write thesis- and time-based exit rules in advance; the one stop you must never move is the one moving against you.