Term Structure of Volatility: Contango vs Backwardation

Key Takeaways

• Term structure of volatility plots ATM IV against expiration; contango (longer > shorter IV) is the normal state roughly 80 percent of the time since 2010.
• VIX/VIX3M above 1.0 signals backwardation, near-term IV exceeds 3-month IV, historically coinciding with major drawdowns including 2008, 2015, 2018, and 2020.
• A common mistake: treating VIX backwardation as an automatic buy signal, the ratio is informative on average but has produced many false positives in multi-week drawdowns.
• VXX and UVXY holders pay persistent roll yield in contango, VIX futures cost more to roll each month, producing annualized drag that can exceed 50 percent in quiet markets.

What It Is

Plot implied volatility against time to expiration for a fixed strike (usually at-the-money) and you get the term structure. For the S&P 500, Cboe publishes several benchmark IVs at standard tenors: VIX9D (9 days), VIX (30 days), VIX3M (3 months), VIX6M (6 months), and VIX1Y (1 year). Each is computed from SPX options of that maturity. Together they form the market's forward view of volatility.

An upward-sloping term structure, with longer-dated IVs above shorter-dated IVs, is called contango. A downward-sloping term structure, with shorter-dated IVs above longer-dated, is called backwardation.

The Intuition

Volatility is mean-reverting. When volatility is low, the market knows a shock is eventually coming, so longer-dated options carry a bit more IV than short-dated ones, producing contango. When volatility is high, the market knows things usually calm down again, so short-dated IVs reflect current panic while longer-dated IVs price the return to normal, producing backwardation.

That mean-reversion logic is why the VIX futures curve is in contango roughly 80 percent of the time since 2010. The slope is the market's estimate of how quickly volatility will revert to its long-run average. The rare inversions are the market saying "near-term risk is much higher than normal and we are not sure it will calm down quickly."

How It Works

The VIX term structure in numeric form might look like this on a calm day:

VIX9D  12.5
VIX    13.5
VIX3M  15.0
VIX6M  16.0
VIX1Y  17.0

Upward sloping. Expected future realized vol trends toward the long-run average (historically around 18 to 20 for SPX). The ratio VIX / VIX3M is frequently used as a regime indicator. Values below 1.0 are normal (contango). Values above 1.0 indicate stress (backwardation).

On a stress day during a selloff, the curve can invert sharply:

VIX9D  42.0
VIX    38.0
VIX3M  30.0
VIX6M  26.0
VIX1Y  22.0

Short-dated IV is bid up because put protection is in urgent demand. Longer-dated IV rises less because over a year the market expects volatility to revert. The ratio VIX / VIX3M at roughly 1.27 is a textbook backwardation read.

Similar structures exist on individual stocks, especially around discrete events. A 30-day IV might sit at 25 while the 7-day IV around an earnings announcement spikes to 60, then the 60-day IV is back to 28. This is the event term structure and it is what implied move calculations use.

Worked Example

On October 24, 2008, during the financial crisis, VIX peaked around 80 while VIX3M was in the mid-50s and longer-dated VIX futures in the 40s. That steep backwardation reflected extreme near-term fear combined with an expectation that conditions could not stay that bad for a year. A trader observing the ratio VIX / VIX3M above 1.3 would have read it as a historically stressed regime.

Empirically, VIX/VIX3M inversions have coincided with major drawdowns in the S&P 500 (2008, August 2015, February 2018, March 2020). After those inversions, forward returns on the index have historically been above average, not below, because the market tends to overshoot on the downside when short-dated vol spikes. The ratio is used by some practitioners as a contrarian entry signal, though it is hardly foolproof.

On the flip side, persistent deep contango (VIX / VIX3M well below 1) often coincides with complacent markets where volatility is underpriced and long-volatility positions can pay off asymmetrically.

Common Mistakes

1. Treating an inverted curve as an automatic buy signal. Backwardation coincides with historically high forward returns on average, but the dispersion is enormous. Calling a bottom with the VIX ratio alone has produced plenty of false positives during multi-week drawdowns.

2. Ignoring roll yield in VIX-linked products. ETPs like VXX and UVXY roll VIX futures daily. In contango, that roll produces a persistent drag because each day the fund sells a cheaper near-month future and buys a more expensive next-month future. Over years the drag can exceed 50 percent annualized. The term structure is not just information, it is a direct P&L input for these products.

3. Confusing VIX levels with VIX term structure. A VIX of 20 with a steeply inverted curve is more stressed than a VIX of 22 in flat contango. Looking only at the spot level misses half the signal.

4. Using spot VIX to price single-stock event moves. Single-stock term structures tent up around earnings and flatten after. Treating the 30-day IV as the event IV under-weights the near-date premium buyers pay specifically for the announcement day.

5. Assuming the shape persists. The term structure regime can flip in hours. February 5, 2018 saw VIX roughly double in a single session, moving the curve from contango to backwardation. Hedging assumptions built on "the curve will stay in contango" have repeatedly been wrong when they mattered most.

Frequently Asked Questions

Q: What is the term structure of volatility in simple terms? The term structure shows how implied volatility changes from short-dated to long-dated options on the same underlying. Normally short-dated IV is lower than long-dated IV (contango), but during market stress it flips, short-dated IV spikes above long-dated IV (backwardation).

Q: How does the term structure affect investment decisions? It tells you whether the market sees risk as near-term or structural. Steep backwardation signals acute fear; the VIX/VIX3M ratio above 1 has historically been followed by above-average forward index returns, though with high dispersion.

Q: What is a real-world example of term structure backwardation? During the 2008 crisis, VIX hit roughly 80 while VIX3M was in the mid-50s. The ratio above 1.3 was extreme backwardation, signaling panic focused on immediate survival rather than long-term structural risk.

Q: How can investors use the term structure practically? Watch the VIX/VIX3M ratio. Values below 0.9 in deep contango often signal complacency where long-volatility positions are historically cheap. Values above 1.1 in backwardation signal stress and have historically been contrarian buy signals for equities, though not reliable timing tools.

Q: How is the term structure of volatility different from volatility skew? Skew varies across strikes at one expiration; term structure varies across expirations at one strike. Together they define the full two-dimensional implied volatility surface. Separately, each carries different information about the market's risk assessment.

Sources

1. Cboe. "VIX Term Structure." https://www.cboe.com/tradable-products/vix/term-structure/
2. Cboe. "Inside Volatility Trading: Is VIX Backwardation Necessarily a Sign of a Future Down Market?" https://www.cboe.com/insights/posts/inside-volatility-trading-is-vix-backwardation-necessarily-a-sign-of-a-future-down-market/
3. Macroption. "VIX Futures Curve." https://www.macroption.com/vix-futures-curve/
4. Natenberg, S. Option Volatility and Pricing: Advanced Trading Strategies and Techniques. McGraw-Hill. https://archive.org/details/optionvolatility00shel

Disclaimer

This article is educational content only and is not financial advice. Nothing here is a recommendation to buy, sell, or hold any security. Consult a licensed advisor before making investment decisions.