Reference
Free to readTerm Structure FAQ & Glossary
Quick answers to the questions traders actually ask about the VolDex® term structure — plus the vocabulary, defined.
Frequently asked
Why at-the-money, and not 25-delta or another strike?
At-the-money strips out skew — the directional bias baked into out-of-the-money options. VolDex® measures pure ATM implied vol so the term structure reflects the market's price for time and uncertainty, not for crash protection. Compare a 25-delta and the curve would move with skew, not with the regime.
What's a "good" TermDex® level?
There's no fixed number. TermDex is read against each asset's own history. Positive is the normal, calm (contango) state; negative means the curve has inverted into backwardation — stress. What matters is where it sits in its own range: TermDex steeper than it's been all year is a different statement than "slightly positive."
Which expirations does the term structure use?
Ten fixed tenors, in days: 7, 15, 30, 60, 90, 120, 150, 180, 270, and 360. VolDex is computed at each and interpolated to land exactly on the tenor, so the curve is comparable across time and across assets.
Contango or backwardation — which is "normal"?
Contango (upward slope) is normal and calm. Backwardation (downward slope) is abnormal and signals acute near-term risk. The front end gets bid when traders expect more realized volatility right now than later.
How is this different from a single implied-vol number?
A single number tells you the level of fear at one horizon. The term structure tells you the relationship between horizons — whether risk is priced right now or down the road. The slope is the signal a single level can never give you.
Why does one tenor sometimes bump above its neighbors?
That's an event kink — extra uncertainty priced into the expiration that first captures a known catalyst (earnings, a Fed decision, a data print). It's not a stress inversion. The Event Volatility Isolation tool quantifies how much of the bump is the catalyst.
What trade does the term structure point to?
The shape dictates the structure. Steep contango rewards selling the rich long end against the cheap front — calendars and diagonals. A front-end inversion warns anyone short near-dated premium and sets up a snap-back trade. You don't trade the curve directly; you let it tell you which structure has the wind at its back.
Which underlyings are covered?
Eleven: SPY, QQQ, IWM, EEM, IEF, TLT, HYG, GLD, SLV, IBIT, and VXX — equity, rates, credit, gold, silver, bitcoin, and the VIX-futures complex.
How often does the curve update?
It computes live off the option chain through the session; the "Updated" timestamp shows the last refresh. Today's intraday curve is plotted automatically against yesterday's close.
Can I export the data?
Bulk CSV export of an underlying's full history is an Everything-tier feature.
Does an inversion guarantee a selloff or a snap-back?
No. Backwardation describes how the market priced risk on a given day; it is not a forecast. Most inversions resolve as the shock fades, but not all, and not on a fixed timetable. The discipline is reading the regime, not predicting the outcome.
Is VolDex the same as VIX?
No. VolDex is a pure ATM implied-vol measure computed per underlying across fixed tenors. It avoids the distortions that skew introduces into headline volatility measures, and it's available on every ETF we cover, not just one index.
Glossary
At-the-money implied volatility, computed from the live option chain via put-call-parity forward and a closed-form method, stripped of skew.
A single number summarizing the slope of the VolDex term structure. Positive = contango; negative = backwardation. Read against each asset's own history.
VolDex plotted across the ten fixed tenors, shortest to longest — the shape of how the market prices volatility through time.
Upward-sloping curve; long-dated vol above the front. The calm, normal shape.
Downward-sloping curve; front vol above the back. A stress signal.
A point on the curve, measured in days to expiration (7 through 360).
A local bump where one tenor is bid above its neighbors because it captures a known catalyst.
The volatility implied between two future dates — what the curve's slope between tenors encodes.
Short a near-dated option, long a further-dated option at the same strike — the natural expression of a term-structure view.
A calendar with different strikes on the two legs — adds a directional or skew tilt to the term-structure trade.
The extra volatility long-dated options carry over short-dated in a normal, contango market.
Free reference. The live tool and its data come with a plan — ETFs (ETF Analytics), single names (ETF + Equities), full history & CSV (Everything).
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