Implied Volatility, Skew, and Term Structure Explained

Implied volatility is the market’s forecast of future price movement, baked into the price of every option. Skew is how that forecast varies across strikes. Term structure is how it varies across time. Together, IV, skew, and term structure form the volatility surface, which is the highest-density view of what the options market is pricing about future risk. Understanding it is the difference between trading options mechanically and trading them with a read on what the market actually believes.

This guide covers all four concepts in order: implied volatility itself, then skew, then term structure, then how they combine into the surface. It closes with how crypto options-aware traders actually use these signals on BTC and ETH.

What is implied volatility?

An option’s price has two components: intrinsic value (how in-the-money it currently is) and time value (how much it costs for the optionality of being in-the-money before expiry). The time-value component depends on how much price is expected to move between now and expiry. If you take an option price and solve the Black-Scholes model backward for the volatility input that reproduces that price, you get implied volatility.

IV is annualized by convention. A BTC option trading at 60% IV implies the market expects a one-standard-deviation move of 60% over a year, scaled down for the actual time to expiry. The actual one-day expected move is roughly IV / sqrt(365), so 60% IV implies a daily one-sigma move of about 3.1%.

Implied vs realized volatility

Realized volatility is how much price has actually moved, measured over some window. Implied is what option prices say price will move. The two diverge constantly. The persistent gap, where implied tends to sit above realized, is called the volatility risk premium and is the structural reason that selling options has a positive expected value over long horizons.

The actionable read is the ratio of implied to realized. When realized is running well above implied, options are cheap. When implied is well above realized, options are expensive. Many crypto vol strategies are nothing more than this ratio applied with risk management.

BTC DVOL and ETH DVOL

Deribit publishes a 30-day forward-looking IV index for BTC (DVOL) and ETH (ETH DVOL) calculated from a basket of options across strikes, similar in spirit to the VIX for SPX. These indices are the closest single-number summary of crypto IV. They spike during crashes, suppress during low-vol consolidations, and front-run major macro events by hours to days.

IV skew

Skew is the relationship between implied volatility and strike for a single expiry. If options market makers priced every strike on the same expiry at the same IV, skew would be flat. They do not. Different strikes trade at different IVs because the demand for protection and exposure is asymmetric.

How to read skew

The standard way to express skew is the difference in IV between an out-of-the-money put and an out-of-the-money call at the same distance from spot, usually 25-delta on each side.

• Put skew (negative skew): 25-delta puts trade at higher IV than 25-delta calls. The market is willing to pay more for downside protection than upside exposure. This is the default state in equities and the typical state in crypto during corrections and bear phases.
• Call skew (positive skew): 25-delta calls trade at higher IV than 25-delta puts. The market is willing to pay more for upside than downside protection. This is rare in equities and shows up in crypto during late-stage bull markets and short-squeeze regimes.
• Flat skew: The market has no strong bias. Often appears in coiled, low-conviction consolidation regimes.

Skew tells you what the options market fears. If puts are expensive, the market is paying for downside. If calls are expensive, the market is paying for melt-up. The flip from one to the other is one of the more reliable late-cycle signals in crypto.

What changes skew

Skew is driven by two forces: customer demand for protection or exposure, and dealer willingness to take the other side. When customers buy puts in size, dealer inventory becomes short puts, and dealers raise put IV until the position is acceptable. When customers buy calls in size during a rally, the same effect happens on the call side.

Skew compresses after risk events resolve and expands as new risks build. A clean read on skew over a multi-week window often front-runs the actual move. Put skew rising into a quiet market is a warning. Call skew rising during a rally is a signal that the rally has become consensus.

IV term structure

Term structure is the curve of implied volatility across expiries, holding moneyness constant. It tells you whether the market expects more volatility soon or later.

Contango

When longer-dated options have higher IV than shorter-dated options, the curve is in contango. This is the normal state. The market is pricing in cumulative uncertainty that grows with time. Calm spot markets tend to produce smooth, upward-sloping vol curves.

Backwardation

When shorter-dated options have higher IV than longer-dated, the curve is in backwardation. This is a stress signal. The market is pricing more risk in the next two weeks than over the next three months. Backwardation appears in two cases: a known catalyst is imminent (FOMC, ETF decision, hard fork), or the market is already in active turmoil and short-dated premiums are bid for protection.

Reading term structure shifts

The shape of the curve is less informative than how it changes. A curve flattening into an event tells you the event premium is being priced in. A curve steepening after an event tells you the uncertainty has resolved and front-end vol is being sold. A curve flipping into backwardation tells you the market is shifting from anticipation to defense.

The volatility surface

Putting strike, expiry, and IV together gives you the volatility surface, a three-dimensional view of the entire options market. Skew is a horizontal slice at a given expiry. Term structure is a vertical slice at a given moneyness. The surface is both at once.

On the surface, you can see things that are invisible in any single dimension: where IV is rich on the wings of the next quarterly, where the front month is cheap relative to the back month at the same delta, where the put surface has steepened faster than the call surface. These are the dislocations relative-value vol traders harvest.

How traders actually use IV

IV in isolation is rarely actionable. It becomes actionable relative to something else.

• Vol regime filter. If realized vol is running above implied for a sustained period, the market is trending and trend systems should be sized up. If implied is well above realized for a sustained period, the market is ranging and mean-reversion strategies tend to work better.
• Direction confirmation via skew. A breakout with put skew compressing is a stronger long signal than a breakout with put skew expanding. The first means the market is leaning long; the second means the market is paying for protection even as price rises.
• Event setup via term structure. When the front month is rich relative to the next month into a known catalyst, the market is paying for short-dated protection. Selling that front-month richness against a long position in the next month is a classic event trade.
• Surface dislocations. A wing on the quarterly surface that has lifted disproportionately versus its neighbors is often a sign of one large customer flow. Knowing where the flow happened is sometimes worth more than the trade against it.
• Spot trading overlay. Even spot-only traders benefit from reading IV. Position size should adjust with regime. Stops should sit outside expected one-day moves derived from current IV. Holds should match the time structure that is being priced.

Crypto IV specifics

The mechanics of IV are universal, but crypto has structural features that change how the surface behaves.

• Twenty-four-hour markets. No close, no opening auction. The surface evolves continuously, and weekend gaps that drive equity skew do not exist.
• Weekly cadence. Friday 08:00 UTC weekly expiries are the dominant short-end anchor. The front-week IV behaves more like a SPX 0DTE than a traditional weekly, with sharp pinning and crush patterns.
• Quarterly liquidity dominance. The last Friday of March, June, September, and December carry the most open interest of the year and anchor term structure more than monthly expiries do.
• Venue fragmentation. Deribit dominates but Bybit, Binance, and OKX are growing. Aggregating IV across venues is increasingly important for an accurate surface.
• Asymmetric crash skew. BTC put skew can move violently during liquidation cascades because crypto spot moves faster than equity spot in tail events. Skew compresses just as fast on the rebound.

Common misconceptions

“High IV is bullish or bearish.” IV is directionally neutral. It rises in both crashes and melt-ups. The information is in skew, not in the level itself.

“IV always reverts to a mean.” It does over long horizons, but the path can be punishing. Selling vol because IV is “high” without sizing for tail outcomes is the most reliable way to blow up a vol book.

“Skew is the same in all markets.” Equity index skew is structurally negative because pension funds and asset managers are perpetually long underlying and want puts. Crypto skew has flipped to call-positive multiple times during bull markets. Do not assume equity-style skew applies.

“The volatility surface is a black box.” It is just a chart. It looks intimidating in three dimensions but reads cleanly as a heatmap or as simultaneous skew and term structure plots. The information density is high but the inputs are accessible.

Frequently asked questions