How stops work in a market-neutral trade
3 min read · education, not advice
Market-neutral does not mean risk-free. A pairs trade is a bet that a stretched gap between two stocks closes. If the gap keeps widening instead, both sides of the trade can lose at the same time — the stock that was bought keeps falling behind while the one sold short keeps running ahead.
A stop on the gap, not on a stock
In a single-stock trade, a stop is usually a price on that stock. In a pairs trade the thing being measured is the gap, so the stop is set on the gap: if the distance between the two stocks stretches past a pre-set level, the setup is treated as wrong and both legs are closed together.
Closing only one leg would leave an ordinary, one-directional position on — no longer a pairs trade at all.
Why the stop is set before the trade
The moment a gap is widening is the moment it is tempting to wait "just a little longer". Deciding the exit in advance, from the same statistics that defined the entry, removes that decision from the worst possible time. PairsCopilot sets the safety stop from the model before a signal is published, and the full report states it.
What a stop cannot do
- Prices can jump overnight or on news, past the stop level, so a loss can be larger than planned.
- Short positions can lose more than was invested, because there is no ceiling on a stock's price.
- A stop-out is a normal outcome, not a malfunction — PairsCopilot lists stopped signals with the same prominence as the ones that closed.