LiquidityLevelsOvernight High and Low
The overnight high and low are the highest and lowest prices reached in the electronic session before the US cash open. They are among the most-watched levels at 9:30 AM ET.
4 min read · Educational, not trading advice
What they are
ES and NQ trade through the night, so each overnight session produces a high and a low. Those two prices frame the range the market built while US cash markets were closed. Because SPY and QQQ options do not trade overnight, these levels are the market public record of what happened between sessions.
Many traders add the prior day high, low and close to the same chart, which gives a map made of the prior session extremes and the overnight extremes. The overlap or separation between the two sets tells part of the story.
How the window is defined
The definition of the overnight session varies. Some traders use the full ETH period from the 6:00 PM ET Globex open until 9:30 AM ET. Others use the period after the 4:00 PM ET cash close. Some use the span between the cash close and the next open but exclude the first hour of the evening reopen. The differences can change the high or low by a few points.
Whatever the convention, it should be stated, because two traders can refer to different overnight highs. LiquidityLevels briefings refer to the structure of the session leading up to each briefing time.
How traders use them
The overnight high and low act as early reference points. When the cash session opens, traders watch whether the market opens inside the overnight range or outside it, and whether it accepts or rejects the extremes. A rejection of the overnight high on the open is often read differently than acceptance above it.
The overnight range also provides a sense of size. A very narrow range suggests a quiet night and possible expansion later. A very wide range suggests a lot has already happened, and the cash session may spend its time responding.
Because they are objective and visible on every platform, these levels tend to attract attention. That does not guarantee reactions, but it means that the market conversation often centers on them.
A routine for the overnight levels
Each morning, mark the overnight high, low and midpoint with a consistent definition. Record the time each extreme was made: an extreme set in thin early-evening trading is different from one made during the London session. Note where the overnight levels sit relative to the prior day high, low and value area.
At the open, watch the first test of each overnight level. Record whether it was accepted or rejected, then compare with the prior session. This kind of record keeping turns a familiar idea into data about how a given market treats these levels.
Overnight levels and options traders
Because SPY and QQQ options open at 9:30 AM ET, overnight levels often define the first strikes of interest. Traders translate the ES and NQ levels into SPY and QQQ prices and compare them with the available strikes. The translation is approximate, so check the ETF chart for the actual price at the open. The overnight levels provide a map but not a decision about which strategy or strike suits a trader.
Worked example
Common mistakes
- Mixing overnight definitions from different sources.
- Treating the overnight high or low as strong support or resistance by default.
- Ignoring thin trading, which can create sharp spikes that distort the extremes.
- Forgetting that the levels refresh every night. Yesterday overnight high is not today level.
How it connects to ES, NQ, SPY and QQQ
Overnight levels are naturally futures levels. The ES overnight high divided by roughly 10 gives an approximate SPY level, and the NQ overnight high divided by roughly 41 an approximate QQQ level. The ratios drift, so use them as orientation.
LiquidityLevels briefings include the key overnight levels in both futures and ETF terms. The free Today level page shows one of them for the latest session.
See it in the live map.
This idea is applied to the current ES and NQ overnight structure every session.