Realized vs. Implied Volatility: A Dangerous Shortcut

The Basic Premise: IV vs. RV

In this article we will focus on Realized vs. Implied Volatility. At the core of many volatility strategies is the belief that options are overpriced when implied volatility exceeds realized volatility. The idea is simple:

• Implied volatility is the market’s forecast of future volatility. It is embedded in the price of the option.
• Realized volatility is a measure of how volatile the asset actually has been, often over the past 10–30 days.

If IV is greater than RV, the option seems expensive, hence, you sell volatility and collect premium. If IV is less than RV, the option seems cheap, perhaps a buying opportunity.

However, this comparison has two major flaws:

1. The timeframes are mismatched.
2. Volatility is model-dependent and not directly observable.

Chat with QUIN on volatility.

Backward-Looking vs. Forward-Looking

The biggest problem with the IV–RV comparison is that realized volatility is a backward-looking measure, while implied volatility is forward-looking.

This creates a mismatch: your P&L depends on what volatility will be in the future, during the life of the option, not what it was in the past.

This is especially problematic in commodities like oil, where volatility regimes shift rapidly. A calm 30-day historical period tells you very little about how volatile the next two weeks will be, especially if there are known catalysts like OPEC meetings, geopolitical risks, or inventory surprises.

“Your P&L does not depend on what happened in the past. It depends on what happens in the future when you hold the position.”

To get a meaningful comparison, you should measure forward realized volatility, the actual realized volatility that occurred after the option was sold. But of course, this can only be known after the fact.

The True P&L Formula: Gamma × (IV – FRV)

To understand how volatility affects trading outcomes, you must go beyond simple IV–RV comparisons. The real formula for profits in volatility selling strategies is:

P&L = Gamma × (Implied Volatility – Forward Realized Volatility)

Let’s unpack this:

• Gamma measures the option’s sensitivity to price moves and increases as expiration nears.
• Implied Volatility is fixed when you sell the option, you lock it in.
• Forward Realized Volatility (FRV) is what actually plays out during the option’s life.

If IV > FRV, you make money. If FRV > IV, you lose money.

This equation shows two key things:

1. You can’t assess strategy performance until after the option expires.
2. Gamma amplifies both profits and losses, especially near expiry, when it spikes.

A Case Study: COVID 2020

Let’s take a real-world example. In early 2020, just before COVID-related chaos, implied volatility on oil was around 35–40%. At the time, this seemed elevated compared to recent realized volatility of ~25%.

Traders’ short volatility looked comfortable until the market collapsed.

As oil prices crashed and volatility exploded, realized volatility jumped to over 140%. This meant that traders had sold options based on an IV of 40%, but were now experiencing actual volatility over triple that.

The IV–RV shortcut would have told you to sell. But the FRV–IV spread was massively negative, resulting in huge losses. This illustrates the critical danger of relying on past volatility as a guide.

Why the Shortcut Still Persists

If the IV–RV comparison is flawed, why do so many traders still use it?

There are several reasons:

• It’s easy to calculate. RV can be computed from historical prices. IV is quoted directly from the market.
• It works, until it doesn’t. In stable regimes, IV often trends slightly above RV, allowing traders to collect premiums.
• It’s institutionalized. Many quant funds and volatility strategies are built around this framework, especially in equities.

But oil markets are more complex. Structural shifts, large position imbalances, and geopolitical shocks can instantly invalidate the assumptions behind the shortcut.

The Hidden Role of Distribution Shape

Another reason the IV–RV comparison is misleading is that volatility is model-dependent. Both IV and RV assume specific distributions, typically log-normal for Black-Scholes models.

But in reality, oil price returns are often not log-normal. They exhibit:

• Fat tails
• Skew
• Jumps and gaps

This means that even if IV and RV look similar, the underlying assumptions are wrong. Comparing them directly is like comparing apples to oranges.

Learn more about Log Returns.

When Does the Comparison Work?

To be fair, there are times when IV vs. RV can be a helpful tool, particularly in calmer markets or in relative terms:

• If IV is extremely elevated due to a known event, and you believe it’s overhyped, selling may make sense.
• If RV is abnormally low, and IV has compressed with it, buying options may be a good bet ahead of catalysts.

But in oil markets, these scenarios are rare and short-lived. You’re better off thinking in terms of scenarios and conditional forward volatility, what you expect to happen, not what already did.

Better Tools for Volatility Traders

If you want to be more accurate, replace the IV–RV shortcut with more robust metrics:

• Implied vs. Forecast Volatility: Use models that forecast forward volatility based on macro factors or technical patterns.
• Term Structure: Analyze the slope of the volatility curve to identify areas of cheap or expensive premium.
• Skew: Look at the difference between call and put implied volatilities. Skew reveals hedging pressure and directional sentiment.
• Options Positioning: Use open interest and dealer gamma exposure to anticipate reflexive volatility moves.

These tools provide context, which is often missing from the IV–RV spread alone.

Final Thoughts: Drop the Shortcut

Comparing implied and realized volatility is not inherently wrong—it’s just dangerously incomplete.

In complex, path-dependent markets like oil, simple backward-looking metrics can lure traders into positions that seem statistically sound but are fundamentally flawed.

To succeed in volatility trading, shift your mindset:

• Focus on forward volatility, not past behavior.
• Understand gamma dynamics, especially near expiry.
• Use scenario analysis, not just historical averages.

Volatility trading is not about what has happened, it’s about what might happen, and how your position responds to it. Chat with QUIN for more.