Reading spread widening as an early warning before price moves

[Shadow Trader]

Sometimes the spread starts to widen a few seconds before price moves. Not by much, a fraction of a pip, but it's noticeable on pairs where spreads are usually steady.

The reasoning is straightforward. Liquidity providers see incoming flow or sense a risk event, and they widen quotes to protect themselves. They may have information about order imbalance that retail traders don't. When the spread blows out, something is about to happen, or has just happened somewhere else.

This is crude, and the cost of the wider spread is a problem on its own. But a few traders use it defensively as a filter: if spread exceeds a threshold relative to its recent average, no new entries.

Some use it offensively, treating a widening followed by a sharp move as confirmation of a breakout. The trade-off is that entries happen at a worse price.

Testing it takes only a spread logger. Record spread every second over a few weeks, mark the moments when price moved more than a few pips in ten seconds, and look at what the spread did in the lead-up.

There are reasons the signal may not hold. Spread changes can reflect a broker's own risk management, not the broader market. A broker might widen quotes because its own exposure has grown. In that case, the widening carries no information about the direction.

Another subtlety is how the platform displays spread. Some show the current spread. Some show the average over the last few ticks. Reading the raw bid and ask directly, from a tick feed, is more accurate.

Testing the idea honestly means defining an event objectively: spread above 2x its trailing average for five seconds, for example. Then recording what happened to price over the next 10, 30, and 60 seconds. With a few hundred events, the average outcome shows up, and so does the variance, which is often large.

Does the spread move before price on your pair, or only after?