A Checklist to Read SPX Levels Before the Open
A pre-open checklist is a short, repeated review of the prices that matter for SPX before 9:30 AM New York time: the Asia and London ranges, the premarket high and low, yesterday's levels, the 20 and 200 averages, Zero Gamma, the walls and today's news. It builds a picture of the day; it is not a list of buy or sell signals.
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What is a pre-open checklist for?
Before the open you already know a lot: how the futures moved overnight, where the index closed yesterday, where its averages are and how dealer hedging is set up. Writing those numbers down in the same order every morning prevents you from skipping one and keeps your reading consistent from day to day, whatever the market is doing.
The goal is to arrive at 9:30 with a clear map of the prices on the screen, not a forecast. The general background is in what to watch in the premarket.
What does the checklist cover?
- Asia and London sessions. Mark the high and low each session made overnight. These often become the first lines the US session reacts to.
- Premarket high and low. Once the 7:00–9:30 window is under way, note the extreme prices and whether futures are leaving the Asia and London ranges.
- Yesterday's maximum, minimum and close. Three prices that the market watched the day before; they frequently appear as support or resistance.
- 20 and 200 moving averages. The 20-period average reacts quickly to recent price; the 200 reacts slowly and is often used to describe the longer trend. On SPX, compare with the same averages on the daily chart.
- Zero Gamma and the walls. Note the Zero Gamma and the Call Wall and Put Wall, and check whether price is above or below Zero Gamma before the open.
- Today's news. Earnings, economic releases at 8:30 AM, central bank comments. A news day in the calendar can change how the levels behave.
In GexFlow, the Premarket Checklist draws these lines on the chart with one click: the Asia and London ranges, the premarket high and low, yesterday's high, low and close, the averages, Zero Gamma and the walls, each shown with its own name. You then read the same map every day in the same place.
How does it look with numbers?
It is 8:45 AM ET. The futures imply 5,020. Your chart shows:
Asia range 4,985 – 5,010 · London range 4,995 – 5,025 · premarket high 5,030, low 4,990.
Yesterday: high 5,040, low 4,960, close 5,000. 20-average about 4,980, 200-average about 5,150.
Zero Gamma 4,975 · Call Wall 5,050 · Put Wall 4,950.
Read in plain words: price sits above Zero Gamma, still inside the London range, and about 20 points above yesterday's close. The Call Wall is 30 points above; the Put Wall and the 20-average are below the overnight low. The 200-average is far above. That is a description of the map, not a prediction.
What are the limitations?
- Gamma levels are estimates of a model. They are computed from the options chain with assumed settings; we do not know who bought or sold each option.
- Some inputs arrive late. Open interest is published with a delay, and the premarket range keeps changing until the last minutes.
- None of the lines is a prediction. Price can cross any of them. The checklist tells you what is on the map before the open, not what the day will do. See common mistakes with gamma levels.
See it on the chart
GexFlow's Premarket Checklist puts all of these lines on the SPX chart in one click, each labeled with its name, so the same review takes the same few steps every morning. You can save the layout in your window and come back to it the next day.
Risk disclosure: GexFlow is an analysis and education tool operated by House Genius LLC. It does not provide investment advice, does not manage money and does not give buy or sell signals. Levels, indicators and statistics describe market conditions and do not predict prices. Trading options involves substantial risk of loss and is not suitable for every investor. Market data may be delayed or inaccurate. © 2026 House Genius LLC.
GexFlow team · Last updated: 2026-10-22 · Pending expert review
Keep reading: What is gamma exposure · Premarket: 4:00 to 9:30 AM ET · Call Wall and Put Wall · See GexFlow pricing.