Markets that never close still run on human schedules. Depth falls noticeably during American holidays and weekends, and the same order size produces a much larger price move.
Market makers are the depth
The visible order book is mostly firms quoting both sides continuously, earning the spread and hedging the inventory they accumulate.
Those quotes are not a public utility. They are posted only while the firm is willing to hold the resulting position, and that willingness varies with conditions.
When quoting is reduced, the book does not vanish but becomes sparse, with wider gaps between price levels and less size resting at each one.
Why holidays specifically
Hedging often happens in markets that do close, including regulated futures and traditional instruments used to offset exposure.
A firm that cannot hedge on Thanksgiving or Independence Day will carry less inventory, which means quoting less size on the venues that remain open.
Staffing compounds it. Risk teams run thin over long weekends, and automated limits are typically set more conservatively when fewer people are available to intervene.
What thin books do to price
Price impact is a function of how much resting size a market order must consume. Half the depth means roughly twice the movement for the same order.
Slippage on execution grows accordingly, and stop orders trigger at levels that would not have been reached during a normal weekday session.
Liquidations amplify this, because forced selling into a thin book pushes price further, which triggers more forced selling in the same window.
Why large moves cluster in quiet hours
The pattern of dramatic weekend moves is less about news timing and more about the market's reduced capacity to absorb ordinary flow.
A position that must be closed for reasons unrelated to the market will move price further simply because fewer counterparties are present to take the other side.
Prices often retrace when depth returns, which is consistent with the move having been a liquidity event rather than a repricing of anything fundamental.
Reading depth rather than volume
Volume reports what already traded, while depth describes what could trade now. The two diverge exactly when it matters most.
A market can show healthy volume while its book is thin, because the same limited liquidity is being traded against repeatedly.
Anyone executing size treats these as separate questions, checking resting depth at the levels they need rather than inferring capacity from recent activity.