Hey Quant X Tribe,
Nvidia reports earnings after the US close on 26 August. That lands before our open on the 27th.
The Fed's Jackson Hole symposium runs 27 to 29 August, the three days straight after.
Two of the market's biggest catalysts of the summer, landing in the same stretch.
Now look at the VIX. It closed at 14.25 on 14 August, the lowest reading of 2026. It has ticked up since, but it is still sitting well below its long-run average.
By that measure, the market looks about as calm as it gets.
But the options chain does not agree.
Contracts expiring across the Nvidia to Jackson Hole window are pricing a premium over the dates around them. The VIX blends every expiry into one 30-day number, so that premium disappears into the average.
Knowing when the market expects a move is not the same as knowing whether that premium is real.
Two Numbers, One Chain
Most traders stop at "high volume" and call it a signal.
Volume only tells you how many contracts traded today. It resets to zero every session.
Open interest tells you something different: how many contracts are still open, carried from one day into the next.
High volume with open interest barely moving is usually just churn. Traders in and out.
High volume with open interest climbing means new positions are being opened and held.
Volume tells you something happened. Open interest tells you whether it stuck.
One practical note before you go looking. Open interest is published the following morning, not live. It is a next-day confirmation, which is part of why volume feels more actionable than it actually is.
A Pattern, Not a One-Off
This is not a one-time quirk of this particular August.
Options-flow analysts track the same expiration cycle repeating quarter after quarter. S&P performance tends to flip direction around options expiration roughly 66% of the time. Volatility contracts into the expiry, then expands once those positions clear out.
Positioning builds ahead of a known event. It unwinds once the event passes.
Structural, not a headline story.
That is the case for relying on data over headlines. Patterns like this repeat. Once you know what to look for, you stop guessing and start reading the signal that is already there.
The Blind Spot Even Open Interest Has
Here is the part most traders never learn.
Open interest is not the full picture either.
A large and growing share of SPX options volume now trades same-day. Recent options-flow commentary puts it at roughly 65 to 70% of SPX volume. Cboe's own published data has run closer to 60%.
Those contracts expire in the same session they are traded.
Open interest is calculated after the close, so anything that expired that day never reaches the next morning's count. Not because the position was closed out. Because the contract stopped existing.
So even open interest, the more reliable of the two numbers, is only telling you part of the story. A better filter than volume alone. Not a complete one.
One correction worth making, because you will hear the opposite: this is not a hidden institutional corner. Cboe's data shows retail makes up more than half of SPX same-day volume. The flow is fully visible in volume. It is open interest that misses it.
The Filter
Heavy volume with open interest flat is noise. Both rising together is conviction.
Then check the expiry.
If the volume is concentrated in same-day contracts, open interest will never confirm it either way.
That is the real gap. Volume can mislead you. Open interest catches part of what volume misses. Neither number, read alone, tells you what actually happened on the chain.
On 25 August, 7:30pm, we are breaking down the Institutional Blindspot options strategy, and how to read positioning that open interest never records.
If you are reading this from your inbox and have not joined our Tribe Telegram yet, that is where the Zoom link and any updates before the 25th will go out, along with more breakdowns like this one.
See you on the 25th!
To your growth,
Quant X Team
Where Data Becomes Alpha
Editor: Eri Eliana
Disclaimer: The views shared here are for educational purposes only and reflect our team's opinions. They should not be taken as financial, investment, or legal advice. Please do your own due diligence before making any financial decisions.
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