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IV crush vs theta decay: which one actually paid you?

Theta decay pays an option seller a little every day. IV crush pays all at once, when implied volatility drops after earnings or big news. Over an earnings week, most of a seller's gain often comes from the crush, and neither one saves the trade if the stock gaps through the strike.

Comparison · 7-minute read · Updated 2026-11-09

The short answer

Both shrink the price of an option you sold, so both put money in your pocket. They come from different places.

• Theta decay comes from time. Each day that passes, an option loses a bit of value. It's slow and steady. See Theta.
• IV crush comes from Implied volatility collapsing. Before earnings, IV is pumped up because a big move is possible. Once the news is out, IV drops, often overnight. Every option on the stock gets cheaper at once.

Over a normal month, theta does most of the work. Over an earnings week, the crush usually does. But both are small next to a big stock move. A gap through your strike beats both.

Side by side

One short put over earnings (hypothetical)

Cedar Point Retail, a made-up stock, trades at $100. It reports earnings Tuesday after the close. On Tuesday afternoon, implied volatility is 80%. You sell the $95 put expiring Friday, 3 days away, for $0.99, so $99.

To split the two forces, we priced the put with the Black-Scholes model in steps, with a 4% interest rate. First, one day passes with IV held at 80%. That change is theta. Then IV drops to 35% on the same day. That change is the crush.

Case 1: the stock barely moves

Cedar Point opens Wednesday at $100.

Most of the gain came from the crush: $59 of $99. The overnight day of theta added $38, and the last two days added just $2. If you'd bought the put back Wednesday morning for $0.02, you'd have kept $97, and the crush would be the biggest single reason.

That's why sellers like earnings. The premium is fat because IV is high, and most of it melts at once when IV drops.

Case 2: the stock gaps through the strike

Now Cedar Point misses and opens Wednesday at $88. IV still drops to 35%.

The crush still happened. It even helped, by $25. But a $12 gap cost $662. The put went from $0.99 to $6.98.

If you held to Friday and Cedar Point stayed at $88, you'd be assigned 100 shares at $95, worth $88. That's −$700 on the shares, plus $99 of premium, for −$601.

Notice the crush shrank in Case 2: $25, not $59. Once a put is deep in the money, most of its price is the $7 it's in the money by. There's little time value left to crush. IV crush protects you least exactly when you need it most.

So which one paid you?

Ask two questions after any trade over earnings:

1. Did IV drop? If yes, part of your gain was crush. Over an earnings week, often most of it.
2. Did the stock stay put? If it moved past your break-even, neither theta nor crush was big enough to matter.

That's the honest trade-off. Selling before earnings collects a rich premium that crush will likely shrink. In exchange, you accept a gap you can't control and can't exit until the market opens. Many sellers either skip earnings entirely or size those trades much smaller. My guide on selling a cash-secured put before earnings goes through that choice.

IV crush explained shows the same drop from the buyer's side. Gamma vs theta explains why moves hurt more near expiry. If you want to know whether IV is high for a stock before you sell, IV rank vs IV percentile compares the two common gauges. For the wheel strategy and every other strategy in one table, see the options strategy comparison chart.

The expected move calculator shows how big a move the current IV is pricing in.

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