Every option price embeds a forecast: the implied volatility (IV) — the market's consensus estimate of how much the underlying will move, annualized, over the option's life. But options don't settle on forecasts. They settle on what actually happens: the realized volatility (RV) — the movement that really occurred. The gap between implied and realized volatility is where options edge lives. This page explains both measures, how to compare them, and how the desk uses IV Rank to decide when to buy premium and when to sell it.

Implied volatility: the market's forecast, priced in

When you look at an option's price, you're looking at implied volatility wearing a dollar costume. Given the stock price, strike, time to expiration, interest rates, and the option's market price, the Black-Scholes formula can be run in reverse to solve for the single volatility number that justifies the price. That number is IV.

IV rises when demand for options rises — before earnings, during market stress, when uncertainty is high. It falls when the event passes or calm returns. Crucially, IV is a price, not a prediction with a track record. It reflects what traders are willing to pay for protection or speculation right now, which includes fear, hedging demand, and positioning — not just a calm statistical forecast.

A single option's IV is noisy. Traders therefore look at the IV of at-the-money options across expirations, or composite measures like the VIX for the S&P 500, to read the overall volatility regime.

Realized volatility: what actually happened

Realized volatility is backward-looking: the annualized standard deviation of the underlying's actual returns over some window — 30 days is the standard. Unlike IV, RV is a fact, not a forecast. You can compute it from price history with a spreadsheet.

The relationship between the two is the whole game. Academic research and decades of market history show that implied volatility tends to overstate realized volatility — options are systematically "expensive" relative to the movement that follows. This volatility risk premium is the reason premium-selling strategies have positive expected value over time: sellers are compensated for bearing the risk that realized vol spikes beyond what was priced in.

But "tends to" is doing heavy lifting. During genuine crises, realized volatility can explode past implied — the premium sellers collect for years can be given back in weeks. The edge is statistical, not a guarantee, which is why the desk sells premium exclusively through defined-risk structures rather than naked: the edge is harvested, but the tail is cut off.

IV Rank: measuring cheap vs. rich

Knowing that IV is "high" or "low" is useless without a reference point — 25% IV is high for a utility stock and low for a biotech. IV Rank solves this by ranking current IV against its own one-year history on a 0–100 scale:

• IV Rank near 0: current IV is at the low end of its annual range — options are historically cheap.
• IV Rank near 100: current IV is at the high end — options are historically rich.
• IV Rank near 50: IV is mid-range — no strong signal either way.

The desk's heuristic bands, applied consistently:

• IV Rank below ~25: favor premium-buying structures — debit spreads, long condors. You're paying up less than usual for the options you buy, and any volatility expansion helps.
• IV Rank above ~50: favor premium-selling structures — credit spreads, iron condors. You're collecting richer-than-usual premium, and the statistical tendency of IV to drift back down works in your favor.
• IV Rank above ~80: premium is extremely rich — attractive for sellers, but respect that extreme IV often accompanies genuine event risk. Size the tail accordingly.

IV Rank is a ranking, not a forecast. High IV Rank doesn't mean IV will fall tomorrow — it can always go higher. It means the odds and payouts favor the seller's side of the ledger, which is a statement about expected value, not about timing.

IV crush: the event-volatility cycle

The most practical application is around scheduled events — earnings, FDA decisions, Fed meetings, CPI releases. IV inflates into the event as traders bid for protection and lottery tickets, then collapses the moment the news is out, even if the stock moves sharply. This IV crush is the number-one killer of long premium held through events.

The mechanics: a stock's options might price a ±8% earnings move. The stock moves ±6% — a big move! — but because the expected move was ±8%, the options still lose value on the IV collapse. Direction was right; volatility was wrong; the trade loses.

The desk's rules for event volatility:

1. Never hold plain long premium through a binary event unless the thesis specifically requires the event's outcome and the pricing is understood.
2. Prefer structures that benefit from IV crush into events — short premium at the body, long premium at the wings for tail protection.
3. Check the expected move (derivable from the at-the-money straddle price) against the thesis. If the thesis needs a bigger move than what's priced, the trade is a lottery ticket, not an investment.

Putting it together

Volatility timing is not market timing. You're not predicting whether IV rises or falls next week — you're measuring where IV sits relative to its own history, choosing structures whose Greeks align with that measurement, and letting the statistical edge compound across many trades. Buy cheap vol, sell rich vol, define the risk on every position, and never let a single event's IV cycle decide the month.