Everyone agrees stop-losses are important. Almost nobody agrees where to put them — so most traders place them where the pain starts ("I can't lose more than $200") instead of where the trade ends. The result is the classic frustration: stopped out by a wick, then watching the stock rally without you.
The principle: invalidation, not pain
A stop-loss should sit at the price where your reason for entering is proven wrong. Bought a breakout above $150? The trade is wrong if it falls back below $148 — the breakout failed. Bought a bounce off $140 support? The trade is wrong below $138, where support broke. In both cases the stop has a reason tied to the chart, not to your feelings.
This is also why the stop must come before position sizing: the stop distance determines your risk per share, which determines your share count (see how to size a position). Pick the stop from the chart; pick the size from the stop.
Give it room to breathe
Stocks don't move in straight lines — they wiggle. A stop placed exactly at support ($140.00) will get tagged by normal intraday noise. Common practice is to place the stop a small buffer beyond the level: below support by a few percent, or beyond the recent swing low. The buffer size should reflect the stock's volatility: a calm blue-chip needs less room than a volatile small-cap. You're buying insurance against noise, and the premium is a slightly larger risk per share — which the sizing formula absorbs automatically by giving you fewer shares.
Three placement methods that work
- Below support / above resistance. For range trades: just beyond the level that, if broken, invalidates the setup.
- Beyond the swing low/high. For trend trades: below the most recent higher low (uptrend) — a break of the trend structure ends the trade.
- Volatility-based (ATR). Place the stop 1.5–2× the average true range away from entry. This scales the buffer to the stock's actual behavior instead of a guess.
What not to do
- Round-number stops. Everyone else's stops are at $140.00 too — that's exactly where the wick goes hunting. Use $139.40, not $140.
- Moving the stop down. A stop you widen when price approaches it isn't a stop, it's a hope. If the invalidation level was wrong, exit and re-plan — don't finance the mistake.
- No stop at all ("mental stops"). Mental stops fail precisely when you need them: in fast moves, or when you're away from the screen. Pro price alerts can watch the level for you.
Stops are half the plan
The stop handles the downside. The upside needs the same discipline: decide before entering where you'll take profit and how much you'll sell there. That's the take-profit ladder — the stop and the ladder together are a complete trade plan.
Educational content only — not investment advice.