Implied volatility (IV) of a stock's options typically rises 30-100% in the week before an earnings announcement, peaks the day before, and crashes back to normal levels within hours of the release. This "IV crush" can make a directionally correct options bet a money loser. Example: Stock X is at £100 with earnings tomorrow. IV is 80%. You buy a £105 call at £4. After earnings, stock jumps to £108. IV crashes to 30%. Your call is worth £3.50 — you lose money despite a £8 favourable move. The correct strategy for trading earnings is to sell premium, not buy it (iron condors, strangles, etc.), or simply avoid earnings entirely until you understand IV mechanics.
The mechanic of IV crush
Option pricing has two components: intrinsic value (in-the-money portion) and extrinsic value (time + volatility premium). Implied volatility (IV) is the market's expectation of future price movement, embedded in the option premium.
Before earnings:
- Stocks have uncertain outcomes — the announcement could move the price 5-20%.
- Options market participants bid up extrinsic value to compensate for this risk.
- IV often doubles from baseline (e.g. 30% to 60%).
After earnings:
- The uncertainty is gone — the result is now known.
- Extrinsic value collapses as IV resets toward baseline.
- The IV reduction translates directly to option price reduction (via Vega).
Worked example — the crush in action
Stock X earnings — directional play gone wrong
Stock X is at £100. Earnings tomorrow. IV is at 75% (elevated for earnings).
You buy a £105 call expiring in 14 days for £4.00 premium. Delta is 0.30. Vega is 0.15.
Earnings: stock jumps from £100 to £108 (+8% — a strong move in your direction).
| New intrinsic value (£108 − £105) | £3.00 |
| Pre-earnings extrinsic value (from IV at 75%) | £3.50 (estimated) |
| Post-earnings IV: drops to 30% (back to baseline) | |
| IV crush impact (45% × Vega 0.15) | −£6.75 of premium |
| Net post-earnings premium estimate | £3.50 (intrinsic £3 + remaining extrinsic ~£0.50) |
| Your option is now worth £3.50, you paid £4.00 | −£0.50 (−12%) |
Even though the stock moved £8 in your direction, IV crush ate the premium. The "right" trade returned a loss.
What you need to know about earnings before trading
- Look at the implied move. The options market prices an "expected move" based on the price of at-the-money straddle. If the straddle is £4 and stock is £100, the implied move is 4%. The stock needs to move MORE than the implied move for a long option to profit after IV crush.
- Historical post-earnings moves. Look at the last 4-8 earnings releases. Did the stock typically move more or less than implied? Stocks with consistent "beats" tend to move more; "miss-prone" stocks move less.
- Time to release. IV peaks in the final 1-3 days before earnings. Buying options 30 days out and selling them the day before earnings (avoiding the crush) is a common pre-earnings strategy.
The right way to play earnings — sell premium, don't buy
If you believe the implied move is overpriced (the market is too uncertain), sell premium via defined-risk strategies:
- Iron condor: sell an out-of-the-money call AND an out-of-the-money put, buy further-OTM call and put for protection. Profits if the stock stays in a wide range.
- Iron butterfly: sell an at-the-money straddle, buy wings for protection. Profits if the stock stays near the current price.
- Short straddle (advanced, risky): sell both an ATM call and ATM put. Maximum risk is unlimited — only for experienced traders with sufficient capital.
These strategies profit from IV crush. If IV drops 50% and the stock stays roughly flat, you collect most of the premium received.
The "earnings calendar" approach
Track earnings dates for your watchlist. For each upcoming earnings:
- Note the date and time (UK: usually evening US time = morning UK time next day).
- Check the implied move (from current at-the-money straddle).
- Compare to historical moves (look at past 4-8 quarters).
- Decide your stance: bullish, bearish, or neutral.
- Choose strategy:
- Strong directional view + large expected move: long call/put 30+ days out (close before earnings to avoid crush).
- Neutral or "implied move is overpriced": iron condor or iron butterfly.
- No view or "implied move looks fair": stay out.
Common earnings-trading mistakes
- Buying long options the day before earnings. You're paying peak IV. The crush will hit you. Almost always loses money.
- Selling naked options into earnings. A 20% gap move could wipe out years of premium income.
- Trading meme stocks through earnings. Implied moves are often 10-15% but actual moves can be 30%+. The risk-reward is gambling-grade.
- Forgetting time of release. Most US earnings are after market close (US time) — moves happen overnight. By the time you can react, the move is done.
- Ignoring sector spillover. A bad NVDA earnings can drag down AMD, INTC, semis broadly. Be aware of correlated positions.
The retail conclusion
For most UK retail options traders: don't trade earnings for your first 12 months. Trade through earnings (hold a covered call position through earnings, for example) is acceptable if the position was opened before IV elevated. Opening new long positions in the week before earnings is almost always a losing strategy at retail size.
If you must trade earnings, use defined-risk premium-selling strategies (iron condors, butterflies) — not long calls or puts.
Sources and methodology
IV crush observations are based on standard options-pricing theory (Black-Scholes + extensions) and empirical data from broker-published implied volatility surfaces. For a personalised options strategy, see the tax adviser editorial recommendation (regulated investment advice requires FCA authorisation). The methodology page documents sources.
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