Fixed-strike volatility tracks the implied vol of one specific strike over time, instead of letting the reference point float with spot. For a desk, that fixed anchor is the cleaner read on dealer positioning: it strips out the mechanical drift that sticky-delta and at-the-money measures fold in, exposing where hedging pressure actually sits.
The volatility surface in one picture
Every listed option carries an implied volatility, and those vols are not a single number. They form a surface: one axis is the strike, or moneyness, the other is time to expiry, and the height is the vol the market is charging at each point. The front of that surface, the near-dated strikes closest to spot, is where dealer hedging lives. Read it well and you can see where the people who have to hedge are leaning. Read it carelessly and you are watching noise.
The catch is that the surface moves for two different reasons at once. Spot moves, and the vol charged at each fixed point moves. Most retail vol education collapses those two into one at-the-money line and calls the result implied volatility. A desk never does. The entire edge is in separating them, and that is exactly what fixed-strike volatility is built to do.
Fixed strike versus floating strike
There are two ways to track a point on the surface. A floating-strike measure follows a moving reference: at-the-money vol, or a constant-delta vol such as a fixed-delta put, re-anchors to wherever spot sits right now. A fixed-strike measure does the opposite. It nails the reference to one actual contract and watches the implied vol of that exact strike over time, regardless of where spot wanders.
This is the distinction Emanuel Derman formalized as sticky-strike versus sticky-delta. Under a sticky-strike regime, each individual strike keeps its own vol as spot moves, and the at-the-money line changes only because a different strike has become the new at-the-money point. Under sticky-delta, the smile slides along with spot, so a fixed strike reprices even when nothing fundamental has changed. Floating measures cannot tell those two worlds apart. Fixed-strike observation can, because it holds the only thing that is genuinely fixed: the contract itself.
| Convention | What stays anchored | What it implicitly assumes | What it shows a desk |
|---|---|---|---|
| Fixed-strike vol | One specific listed strike | Nothing about spot; pure observation | The cleanest change in demand at that strike |
| Sticky-strike | Each strike keeps its own vol | A pinned, range-bound, dealer-led regime | When the tape is calm and positioning is holding |
| Sticky-delta (floating) | The smile shape versus moneyness | A trending regime where the smile rides spot | When vol is repricing with direction |
| At-the-money vol | The point nearest spot | That one summary number describes the surface | A headline, not a positioning read |
What a fixed-strike move tells the desk
Here is the payoff. When a single fixed strike lights up, its implied vol jumps while the rest of the surface stays quiet, you are seeing real demand arrive at that strike. Because the strike is fixed, you have already subtracted the mechanical drift that spot would have injected into a floating measure. What remains is the part dealers actually care about: where size is being put on, where someone is paying up for protection or leverage, and therefore where dealer hedging will have to chase price if it gets there.
That is why fixed-strike vol pairs so naturally with dealer-positioning and gamma work. Gamma exposure tells you how hard dealers will have to hedge around a level; the fixed-strike read tells you whether fresh demand is building at that level in the first place. One is the map, the other is the live traffic. We have published this read in public on X as @Bluedeerc since 2019, marking the strikes that mattered before the move rather than narrating them after.
Spot drifting will repaint an at-the-money line all day and tell you nothing. I watch the vol of the strikes that are not moving. When one of them lights up while spot sits still, that is real positioning, not an artifact of the math. Justin Katz, @Bluedeerc
Where retail vol education stops
This is the nuance that retail vol education skips. The GEX screenshots that circulate online and the alert feeds that quote a single implied-vol number both flatten the surface into one figure. They never separate fixed-strike from floating-strike, so a smile that simply slid along with spot gets reported as new demand, and a genuinely fixed-strike repricing gets lost inside an at-the-money average. The chart looks authoritative. The signal underneath it has been averaged away.
A desk treats the surface as a living object with two independent motions, not a line on a screen. Fixed-strike volatility is the convention that keeps those motions apart, which is why it is the cleaner instrument for the one question that matters: not where vol is, but where the positioning is being built. That is the difference between reading the surface and reading a picture of it.
- Fixed-strike isolates fresh demand from spot-driven drift in a floating measure.
- Sticky-strike behavior flags a pinned, dealer-led regime; sticky-delta flags a trend.
- The near-dated, fixed strikes around spot carry the most hedging information.
- It is a measurement convention, not a recommendation, and not financial advice.
By the numbers
- 0DTE options now account for roughly half of total daily S&P 500 options volume, which is why the front of the volatility surface moves fastest and matters most to a hedging desk . (source)
- The OCC cleared a record of more than 12 billion options contracts in 2024, a scale that makes listed-option positioning a real force in how the surface reprices . (source)
Frequently asked questions
- What is fixed-strike volatility?
- It is the implied volatility of one specific listed strike, watched over time, rather than a measure that re-anchors to wherever spot happens to be. Because the reference point does not move, a change in that vol is a change in real demand at that strike, not an artifact of spot drifting.
- How is fixed-strike vol different from sticky-delta or at-the-money vol?
- At-the-money and constant-delta measures are floating: they follow spot, so their vol can move purely because the reference re-anchored. Fixed-strike vol stays nailed to one strike. The sticky-strike and sticky-delta conventions, formalized in Emanuel Derman's volatility-regime work, describe how a smile is assumed to behave as spot moves, and fixed-strike observation tests which assumption the market is actually living in.
- Why does a desk prefer fixed-strike vol for reading dealer positioning?
- Short-dated contracts carry most of the hedging information: 0DTE options are now roughly half of S&P 500 options volume, so the fixed strikes nearest spot move the surface first (https://www.cboe.com/insights/). Holding the strike fixed isolates fresh demand from the mechanical drift that floating measures bake in.
- Is fixed-strike volatility a trade signal or financial advice?
- Neither on its own. It is a measurement convention that makes dealer positioning legible. It is observation, not a recommendation, and options trading carries substantial risk of loss. Treat it as one input into a process, not a buy or sell instruction.