What Is the Volatility Risk Premium?

Why implied volatility usually exceeds realized — and what sellers earn for closing that gap.

The volatility risk premium is the systematic tendency for implied volatility to run above the volatility that subsequently occurs in the underlying. If SPX options price in 18% annualized volatility over the next month and the index actually moves at 14%, that four-point gap — earned by whoever sold the options — is the volatility risk premium in action. It is not an anomaly or a data artifact. It is compensation, paid by hedgers to volatility sellers for absorbing variance risk. Understanding it begins with separating what you pay from what occurs, a distinction covered in detail in the guide to historical versus implied volatility.

Why the volatility risk premium exists

The VRP is rooted in supply and demand for insurance. Portfolio managers, pension funds, and retail investors consistently buy puts and collars to protect long equity exposure. That structural demand bids up the price of options — and therefore implied volatility — above the actuarially fair level. Options sellers, acting as insurers, require a premium above expected payout to bear the risk that realized vol spikes past implied.

Two reinforcing mechanics deepen the gap:

• Variance aversion. Investors dislike variance, not just direction. They will pay a price above expected loss to eliminate uncertainty, just as homeowners overpay for insurance relative to actuarial value. The seller pockets that overcharge.
• Negative vol-return correlation. Volatility surges most sharply during equity drawdowns — exactly when sellers' losses are most painful. Because selling volatility means bearing concentrated left-tail risk correlated with poor economic states, rational sellers demand extra compensation. The VRP is partly a risk premium in the classic sense: payment for holding an uncomfortable position at the worst possible time.

How to measure it

The simplest measure is the realized spread: implied volatility at option entry minus the realized volatility of the underlying over the option's life. Using monthly SPX options over two decades, this spread has averaged roughly 3–5 volatility points, though it varies substantially across regimes.

A cleaner, model-free version uses variance swaps. A variance swap pays the difference between realized variance (σ²_realized) and the variance-swap strike (K_var), set at entry to make the contract worth zero. Because K_var is determined by the strip of option prices, it represents the market's risk-neutral expectation of realized variance — analogous to implied variance. Empirically, K_var has exceeded subsequent realized variance on average, confirming that variance buyers overpay and sellers collect. The gap K_var − σ²_realized is the variance risk premium, and it tends to be larger in variance space than in volatility space because it compounds nonlinearly with the level of vol.

For index options specifically, you can track this gap through the relationship between the VIX and subsequent realized vol — explored in depth in the post on VIX versus realized volatility. The VIX has historically closed above subsequent 30-day realized SPX volatility roughly 75–80% of monthly observations, a striking regularity for a single statistic.

The payoff profile: small gains, fat left tail

Harvesting the VRP looks attractive in expectation but is negatively skewed in distribution. Consider a 30-day short straddle on SPX, delta-hedged daily. In a typical low-vol month the position collects theta, realized vol comes in under implied, and the P&L is a small positive number. Across most months that pattern repeats. But when volatility spikes — March 2020, August 2015, Q4 2018 — realized vol can blow through implied by 15, 20, or 30 vol points, and the short vol position loses multiples of its average monthly gain in a single week.

The distribution is roughly:

• Positive P&L in the majority of periods (the structural premium)
• Small losses when realized vol modestly exceeds implied
• Severe losses in tail events, often coinciding with broad portfolio drawdowns

This negative skew means that a Sharpe ratio calculated over a short history flatters the strategy. The true risk is in the kurtosis — the infrequent but catastrophic realization. An options pricing calculator can show how rapidly the value of a short straddle moves when volatility spikes 10 points, making the asymmetry visceral rather than theoretical.

Regimes where the VRP compresses or inverts

The premium is not constant. Three environments cause it to narrow or flip negative:

• Crisis onset. At the start of a vol spike, implied vol can lag realized for days. Anyone who sold before the shock is short gamma into a moving market while implied is only beginning to reprice — realized briefly exceeds implied.
• Post-crisis elevated implied. After a shock, implied vol often remains elevated as the market demands higher risk premium. If realized vol mean-reverts quickly while implied stays high, the premium widens; but if the economy stays turbulent, realized can match or exceed implied for weeks.
• Low-vol complacency. In extended calm periods — late 2017 is the canonical example — realized vol compresses toward zero while implied cannot easily follow, since implied vol has a floor driven by option model mechanics and dealer hedging costs. The premium remains positive but may narrow to 1–2 vol points, making net-of-friction strategies marginally attractive at best.

Practical vehicles and the tail-risk caveat

The VRP can be captured through several structures, each with different risk characteristics:

Vehicle	Mechanism	Key risk
Short straddle / strangle	Sell ATM or OTM options, collect premium, delta-hedge	Unlimited loss if underlying gaps sharply
Variance swap (short)	Receive fixed Kvar, pay realized variance at settlement	Convex loss — realized variance enters as σ², not σ
Short VIX futures	Exploit the persistent VIX futures term structure roll-down	Spot VIX spikes can produce rapid margin calls
Covered call writing	Sell calls against long equity to monetize implied premium	Caps upside; doesn't protect full downside

Each vehicle is, in essence, a bet that the option market is pricing more fear than the underlying will deliver. The intellectual case is sound: the premium has been persistent across markets and decades. But the practical caveat is equally important. Because VRP losses cluster with equity drawdowns, a short-vol allocation behaves like leveraged equity in a crisis. Sizing, tail hedges, and drawdown tolerance deserve as much analysis as the expected premium itself. The strategy earns its return not by being clever but by being willing to absorb losses when almost every other asset is also losing — and that is precisely why the premium exists at all.