VIX Futures Basis

Q: What is VIX basis?

Difference between VIX futures (VIX3M proxy) and VIX spot. Positive = contango (normal). Negative = backwardation (stress).

Q: Why approximated from VIX3M?

VIX3M closely tracks 3-month VIX futures without roll complexity. Accurate for regime detection.

Q: Why does VIX Futures Basis matter for trading?

VIX futures basis is the quick-read version of the vol term structure. In contango (positive basis), short VIX / short VXX strategies collect roll yield. In backwardation (negative basis), the same strategies lose money fast while long-vol hedges win. It's the single number that determines whether 'sell VXX and wait' is a profitable or disastrous strategy.

Q: When is VIX Futures Basis good versus bad for a trader?

Positive basis is good for short-VIX and short-VXX systematic trades — roll yield funds the strategy. Negative basis is bad for those same trades and good for long-VIX and VIXY hedgers. Near-zero basis is a transition warning; reduce size on basis-dependent trades.

Canonical definition, formula, interpretation, and API reference.

Definition

Spread between VIX futures (approximated by VIX3M) and VIX spot. Positive = contango (normal). Negative = backwardation (stress).

Formula

Basis = VIX3M - VIX, Basis% = (VIX3M-VIX)/VIX x 100

Approximated from VIX3M vs spot (not actual futures).

Inputs

VIX spotVIX3M

Output

front_monthspotspreadbasis_pctbasis

Interpretation

Positive (~5-10%): normal contango
Near-zero: uncertain
Negative: stress — spot VIX exceeds futures

API Reference

Endpoint

GET /v1/stock/{symbol}/summary

Tier

Free

Response field

macro.vix_futures.front_month, spot, spread, basis_pct, basis

Why VIX Futures Basis Matters for Trading

TL;DR

VIX futures basis is front-month VIX future minus spot VIX. Positive (contango) = calm. Negative (backwardation) = stress.

What it measures: Front-month VIX future price minus the spot VIX index.
What it signals: The near-term vol risk-premium demanded by VIX-futures buyers and sellers.
Why we measure it: Spot VIX can spike without the term structure moving — basis shows whether the spike is priced in or structural.
Who uses it: VIX-futures traders, VXX/VIXY ETP holders, systematic vol desks.

How to read VIX Futures Basis

Positive basis (contango)

Calm expected
Short VXX earns roll
Systematic short VIX futures work
Default regime

Good for: short VIX futures / VXX

Negative basis (backwardation)

Stress regime priced in
Long VIX futures / VIXY work
Short VXX blows up
Rare but critical signal

Bad for: short VIX — good for: long hedges

Near-zero basis

Regime in transition
Minimal roll yield either way
Reduce size
Rare state

Transition

Rules of thumb

Basis drives ETP returns. Contango = VXX decays. Backwardation = VXX rallies. It's math, not prediction.
Pair with VIX term structure. Basis is a one-point snapshot; term structure is the full curve.
Sign matters more than magnitude. A 2% contango and a 10% contango both indicate calm — direction drives ETP P&L.
Event-driven inversions. CPI, FOMC, earnings routinely invert basis briefly.
Free-tier data. VIX and futures data are public — FlashAlpha aggregates in summary.