There is a single moment that quietly decides whether a trader will survive his career, and it arrives over and over again. The position is open. The market is moving against it. And the price is creeping toward the stop-loss — the line you drew in advance, the level at which you promised yourself you would get out. Your finger hovers. A voice says: just give it a little more room. Cancel the stop, move it down twenty points, and let it breathe. What you do in that moment, repeated across thousands of trades, is the whole difference between a disciplined trader and a doomed one. Rule No. 6 exists to make the decision for you, in advance, so that the voice never gets a vote.
The stop that kept moving
Picture the trader who does it the common way. He goes long the DAX and, sensibly, sets a stop fifty points below his entry. So far, perfect. He has a defined risk; if he is wrong, he loses fifty points and no more.
The market drifts against him. Forty points down, forty-five, and now price is closing in on his stop. Here comes the moment. Instead of letting the stop do its job, he cancels it and slides it another twenty or thirty points lower. "It's just noise. It'll turn. I don't want to get shaken out right before it bounces." The fifty-point risk he agreed to has silently become eighty.
Price keeps falling. It approaches the new stop. And having moved it once, moving it again is easy — the principle is already broken, so what's another thirty points? He widens it a second time. Then, because watching a stop get hit is painful and cancelling it feels like control, he does the thing the whole rule exists to prevent: he removes the stop entirely and decides to "manage it manually." He will get out, he tells himself, when it comes back.
Now he has no floor under the position at all. And this is precisely when the market, which owes him nothing, does something he did not plan for — a sharp move on news, an accelerating sell-off, an overnight gap that opens far below where he last looked. The fifty-point loss he had fully controlled at the start has become two hundred, three hundred, whatever the market decides, because he removed the one mechanism that capped it. He did not lose because his entry was bad. His entry came with a perfectly good fifty-point loss attached. He lost because he refused to take it.
Two decisions before you click
The rule has a front half that beginners skip: every position you enter must be justified. Before you put on a trade, you should be able to state plainly why — the reason your homework and the market structure give you to be long or short right here, right now. A trade without a reason is not a trade; it is a bet, and we covered what happens to bettors in the earlier rules.
But the reason is only the first of two decisions you must make before entering. The second is the stop. And the two are connected, because the stop is simply the price level at which your reason for the trade is proven wrong. You are long because you believe the market should go up from here; the stop is the point that says, clearly and without argument, "it didn't, and your premise was mistaken." Setting the stop is therefore not an act of fear. It is an act of intellectual honesty — defining in advance the evidence that would tell you you were wrong, and committing to act on it.
This is why the stop is set at entry and not after. In the calm moment before you commit, with no money yet at risk and no emotion clouding the screen, you can think clearly about where your thesis breaks. Thirty points on the DAX, fifty points — whatever the trade's logic and your risk allow. Once you are in the position and the red number is growing, you can no longer think clearly about that level, which is exactly why the decision must already be made.
The stop is sacred
Here is the heart of Rule No. 6, and it admits no exceptions: once a stop is set, it does not move wider. Ever.
Understand the precise direction of the rule, because there is one legitimate way a stop moves. As a winning trade runs in your favour, you may trail the stop upward to lock in profit — that is the mechanism from Rule No. 5, and it is sound, because it only ever reduces your risk. What is forbidden is the opposite: moving the stop away from the price to give a losing position more room. A stop travels in one direction only — toward safety, never toward greater risk. The moment you slide a stop wider to avoid being stopped out, you have abandoned the plan you made when you were thinking clearly and handed the decision to the frightened version of yourself.
And it is a slope with no bottom. The trader who moves a stop once will move it twice, because the justification is identical each time and the discipline is already gone. Every widening makes the loss you are trying to avoid larger, which makes the next widening more tempting still, because now taking the loss hurts even more. This is how a planned fifty-point loss becomes an account-ending event — not in one reckless decision, but in a series of small, reasonable-sounding adjustments, each one defended in the moment.
What to do when the stop is hit
So the stop is touched. What then? You close the position. That is the entire instruction, and it is not negotiable.
You take the loss — the small, planned, survivable loss you agreed to when you were calm. You do not argue with it, you do not average into it, you do not flip it (Rules 3, 4 and 5 all live here too). You accept that this particular thesis was wrong, and a wrong thesis costing you fifty points is not a catastrophe; it is the ordinary, unavoidable cost of doing business in an uncertain market.
Then you do the productive thing. You step back and analyse. The market has given you new information by hitting your stop, and that information may well point to a better trade. Where is price now? Has the picture changed? Is there a fresh, justifiable entry — perhaps even in the same direction, but from a level that now makes sense? A stop being hit is not a verdict on you as a trader. It is the closing of one position and the opening of a clean slate from which to make your next considered decision. The loss is tuition, and you have already paid it; the only waste would be to refuse the lesson and let it grow instead.
Why trading without a stop is ruin
Step back to the principle. The reason a stop is non-negotiable is the same reason Rule No. 2 told you there is no hundred-percent chance: you never know what the market will do, and you never know when something will arrive that no analysis could have predicted. A stop is your insurance against the unforeseeable. With it, the worst case is defined and survivable. Without it, the worst case is whatever the market feels like inflicting — and a single such event, on a single unprotected position, can undo years of careful work.
It is worth knowing that a standard stop is not a perfect guarantee: in a fast market or on a price gap, your order can be filled some distance beyond your stop level, a slippage you cannot fully control. For exactly this reason, many CFD brokers offer a guaranteed stop-loss order, which closes you out at your exact level no matter how violently the market gaps, usually for a small premium. But the choice between a standard and a guaranteed stop is a detail. The rule itself is absolute, and it comes before any such refinement: you do not enter a position without one.
The bottom line
Never trade without a stop. Justify every position before you take it, set the stop at the moment of entry as the level where your reasoning is proven wrong, and then leave it alone — moving it only ever toward safety, never wider to spare yourself a loss you agreed to accept. When it is hit, close the trade, take the small loss without complaint, study the market afresh, and look for the next honest entry.
The stop is the seatbelt of trading. It is uncomfortable, you will mostly not need it, and the one time you do, it is the only thing standing between an ordinary day and a disaster.