When you sell a short strangle, you are basically making two bets at once. You are betting that the market will not go up too much. And you are betting that the market will not go down too much. As long as it stays in the middle, you keep the money. That is the whole idea.

Most traders learn this strategy with one big assumption baked in: the put side is the dangerous one. Markets fall faster than they rise. The downside is where you get hurt. Almost every options book on the shelf says it.

But the question is, does that actually happen when you look at real trades?

We pulled 10 years of SPY options data and tested 61 real strangles to find out. Both sides sold at 17 delta. Both expiring in about 45 days. We tracked which side got crossed, when, by how much, and what happened next. The answer was the opposite of what we expected, and it should change how you think about which side of your trade actually carries risk.

Part 1: The Concepts – Let’s Start Simple

Before we get to the numbers, let us slow down and explain what we are actually measuring. Skip this section if you already trade strangles. Read it carefully if you are newer.

A short strangle is two trades joined together. You sell a call (a bet on the market going up) above where the price is right now. You sell a put (a bet on the market going down) below where the price is right now. Both expire on the same day. As long as the market stays between your two bets until that day, you keep all the money you collected. That is your win.

If the market pushes above your call, you start losing money on the call side. If it falls below your put, you start losing money on the put side. We call that crossing of your strike a “breach.” A breach is just a fancy word for “the market reached your line.”

For this study, we picked a very specific setup. Sell the call at 17 delta. Sell the put at 17 delta. Both with about 45 days until they expire. The 17 delta level means the market thinks there is roughly a 17% chance each side will end up in trouble. Most option sellers use 17 delta because it gives you a healthy buffer without making the premium too small to be worth collecting.

In a perfect world, both legs would be equally risky. They are sold at the same probability. They should behave the same way. But the real world is not perfect, and SPY is not a coin flip. SPY tends to drift higher over time. That drift is the most important fact in this entire study, and we will come back to it.

One more definition. When we say “breach at any time before exit,” we mean the market touched your strike at any point during the trade. Not just at the very end. Even if it touched and bounced back, that still counts. Why? Because that is when the real-world stress hits. That is when your account looks ugly. That is when you are tempted to close in panic. So we count it.

For this study, we ran 61 trades over 10 years. One trade every 45 days, no overlap. We then looked at three different ways to close each trade. Close at 25% of max profit. Close at 50% of max profit. Or hold to the end. We used realistic prices: you sell at the bid (the lower number), you buy back at the ask (the higher number). No magic mid-prices, just what you would actually have paid in a real account.

Part 2: What 10 Years of SPY Data Actually Shows (2016-2026)

The dataset is large. About 752,000 individual option contract observations. 2,505 trading days. 61 real strangles. Ten full years that include the slow grind of 2016 to 2017, the Volmageddon shock of February 2018, the Q4 2018 selloff, the 2019 Powell pivot rally, the COVID crash of 2020, the 2022 bear market, and the AI bull run of 2023 to 2025. If you wanted to break this strategy, those are the years to do it in. The data covers all of them.

The volatility environment over this period was about average. SPY’s implied volatility hovered around 17.7% on average. In calm years it dropped near 13.5%. In stressed years it pushed up to 21.8%. Nothing about this 10-year window is unusual. It is a fair test.

But the volatility level is not the interesting part. The interesting part is what happened to each side of the trade once the trade was live.

Here is the headline:

The call leg got crossed on 41.0% of trades held to expiration. The put leg got crossed only 13.1% of the time.

That is roughly 3 to 1 in favor of the call side. If both legs were really equally risky, both numbers should sit around 17%. The call number is way above. The put number is below.

Out of 61 trades held to expiration, the call side was crossed 25 times. The put side, only 8.

This was not one strange year throwing off the average. The pattern holds in 7 out of 10 years. The other 3 years (2018, 2022, and 2025) had sustained selloffs, and even in those years, put breaches only caught up to call breaches. Calls were never the safer leg in any single year.

So the data flips the usual story. The call side, the one we are taught to ignore as the “less dangerous” leg, is actually the one that gets tested most often. By a wide margin.

Part 3: Call vs Put Breach Asymmetry

The pattern is even more interesting once you look at how it changes when you close the trade early.

We tested all 61 trades using three different exit rules. Close at 25% profit. Close at 50% profit. Or hold the trade to expiration. Same entries, different exits. Here is what each one looked like:

Same entries, different exits. The call side gets crossed more in every single rule.

Three things stand out.

First, calls beat puts in every single exit rule. No matter how you close the trade, the call side gets tested 2 to 3 times more often than the put side. So this is not a quirk of one specific strategy. It is built into the structure of the trade itself.

Second, exiting early dramatically lowers your risk. If you hold to expiration, your call gets touched 41% of the time. If you close at 50% profit, that drops to 21%. If you close at 25% profit, it drops to 11%. Same idea on the put side. Most of the danger is in the back half of the trade, not the front. By exiting early, you simply skip the dangerous part.

Third, the put side is quiet most of the time. Even when held to expiration, only 8 of 61 trades crossed the put strike. With a 50% target, only 4 did. The put leg is not the active risk in this strategy. It is more like a fire alarm: silent most of the time, but loud when it does go off.

Here is the year-by-year breakdown, hold-to-expiration:

Year	Trades	Call breach	Put breach
2016	7	57.1%	14.3%
2017	6	50.0%	0.0%
2018	6	33.3%	33.3%
2019	5	80.0%	0.0%
2020	6	33.3%	16.7%
2021	6	50.0%	0.0%
2022	6	16.7%	16.7%
2023	6	33.3%	0.0%
2024	6	33.3%	16.7%
2025	6	33.3%	33.3%

Across the whole 10 years, the call side dominated put breaches in normal years and tied in selloff years. It never lost the comparison.

Part 4: The Numbers That Matter – Historical Reference

Let us pull out the most important numbers from this study, the ones that should change how you trade.

Breach Rates by Exit Scenario

This table is the whole study in one place. Same 61 trades. Three different exit rules. Very different outcomes.

Metric	25% target	50% target	Hold to exp
Win rate	95.1%	90.2%	73.8%
Avg profit per trade (% of credit)	-4.0%	+6.9%	+0.3%
Total profit over 10 years (per contract)	$23	$62	$55
Avg days in trade	10.6	17.3	33.9
Call breach during trade	13.1%	21.3%	41.0%
Put breach during trade	6.6%	6.6%	13.1%

Read this table slowly. The 50% profit target made more total money than holding to expiration ($62 vs $55), with way less time in the market and way less breach risk. The 25% target won 95% of trades but only made $23 total because the wins were too small to overcome the bid-ask spread. The middle option was the winner on every measure that mattered.

IV at the 17-Delta Level

Implied volatility (IV) is just a fancy word for how scared the market is. Higher IV means option prices are higher. Lower IV means they are cheaper.

Here is what the IV numbers look like at 17 delta:

2016 to 2020:

• Call IV averaged about 13.6%
• Put IV averaged about 20.1%
• Puts cost about 1.48 times more

2021 to 2026:

• Call IV averaged about 14.3%
• Put IV averaged about 21.4%
• Puts cost about 1.50 times more

The market charges about 50% more for puts than calls at the same delta.

So the market charges you about 50% more for puts than for calls at the same delta. That seems strange, right? If calls get breached more often, why are puts more expensive?

Here is the answer. The market is not pricing how often each side breaches. It is pricing how big the move is when the breach happens.

When calls got breached in our data, they only went 1.8% past the strike on average. Small misses. When puts got breached, they went 6.3% past the strike on average, with one trade going 25% past the strike during the COVID crash. That is what the higher put price is paying for. Not frequency. Magnitude.

In simple words: calls breach often but barely scrape past. Puts breach rarely but go deep when they do. Two different kinds of risk, sold at the same delta.

IV Environment Across the Decade

Just to round out the picture, the broader IV environment looked like this:

• Average IV (2016 to 2020): about 17.4%
• Average IV (2021 to 2026): about 17.8%
• Combined average: about 17.7%
• Range over the decade: roughly 13.5% to 21.8%

Why does this matter? Because higher-IV environments give you wider strangles with more breathing room on both sides. Lower-IV environments give you tighter strangles where small moves can hit your strikes. Knowing where IV sits today is a useful sanity check before putting on a new trade.

Cumulative Profit Over the Decade

Here is the chart that shows how each strategy compounded over time:

Cumulative profit per contract for each exit rule, January 2016 to March 2026.

The 50% target trader (the gold line) ended up at about $62 per contract. The hold-to-expiration trader (the orange line) ended up at $55. The 25% target trader (the green line) ended up at $23.

You can see the COVID drop in March 2020 hit all three strategies. That was one bad trade we could not avoid no matter what. But notice how the gold line recovers faster and pulls ahead by 2022. That is the small edge from exiting earlier on dozens of normal trades, adding up over a decade.

Part 5: Why Calls Tend to Get Breached More Often

We have shown the pattern. Now let us explain it. Three reasons, all rooted in how SPY actually behaves.

1. SPY Drifts Up Over Time

This is the biggest reason, and the simplest one.

SPY tends to go up. Not every day. Not every month. But over time, yes. Here are the numbers:

• 10-year SPY return: about 299.5%
• Average annual return: about 14.9%
• Probability of SPY being higher 45 days later: about 67%

Imagine a slow conveyor belt that nudges the market upward, just a little, day after day. That is SPY’s drift. In any 45-day window, the market drifts up by about 1% to 2% on average. That tiny push is enough to chew through a meaningful chunk of your call-side buffer.

This is not random luck. It is a real feature of the U.S. stock market. Companies grow. Earnings expand. Investors buy. The market climbs. That is the whole reason anyone owns stocks in the first place. And that drift is the engine that pushes price toward your call strike, again and again.

2. Strikes Are Not Symmetric Either

The second reason is geometric. When you sell a 17-delta strangle, the call strike and put strike do not sit at equal distances from the current price.

• Average call strike distance from spot: about 5.0%
• Average put strike distance from spot: about 6.5%

So on top of SPY drifting toward the call, the call strike was actually closer to the price to begin with. In our 10-year sample, the call leg had less buffer than the put leg. Combine that with upward drift, and you get exactly what the data shows. Frequent call breaches. Quiet put leg.

3. The Market Prices Magnitude, Not Frequency

This is the part that confuses most option sellers, and it is worth taking slow.

The market charges you more for puts than calls at the same delta. Most traders see that and assume it means puts are riskier. They are not, at least not in the way most people think.

What the higher put price is really paying for is the size of the move when it happens. When calls breach, they slip past the strike by a tiny amount. When puts breach, they crash through the strike. The market knows this. That is what it is pricing.

So:

• Calls = high frequency, low impact. They breach often but barely.
• Puts = low frequency, high impact. They breach rarely but hit hard.

Both are real risks. They just need different management styles. Most option sellers manage them the same way and get burned because they are reading the market signal wrong.

4. Most Damage Happens Late in the Trade

The fourth pattern is about timing, not direction. Compare these breach numbers:

• Call breaches with 25% target exit: 13.1%
• Call breaches holding to expiration: 41.0%
• Put breaches with 25% target exit: 6.6%
• Put breaches holding to expiration: 13.1%

Notice how the numbers triple when you go from “exit early” to “hold to expiration.” That tells you something important. Most of the breach risk lives in the second half of the trade.

Why? Because in the first half, the strikes are far from the price and time decay is working in your favor. In the second half, gamma builds up (small moves in the underlying cause big moves in the option price),

most of the time decay has already been collected, and the strikes are easier to reach if the market gets active. The risk is back-loaded.

This is why exiting early works so well. You bank the easy theta decay in the front half and skip the gamma trouble in the back half.

So overall, four forces tilt risk toward the call side: SPY’s upward drift, closer call strikes, the IV skew that hides what is really being priced, and the back-loaded nature of breach risk over the trade’s life.

Part 6: Practical Framework for Short Strangles

So what does this mean for how you actually trade? Four practical takeaways.

Watch the Call Side, Not the Put Side

This is the biggest mental shift the data demands.

You have probably been trained to watch the put. Set alerts on the put. Worry about the put. Plan for the put. The data says you are watching the wrong leg.

Going forward, set price alerts on the call strike. Decide in advance how you will manage a call breach (roll up, close, or accept). Mentally rehearse the call side as your day-to-day risk.

The put side will mostly take care of itself in normal years. Save your defensive attention for the call.

Use a 50% Profit Target as Your Default Exit

Out of the three exit rules tested, the 50% profit target produced the best overall outcome. The math works because:

• The 50% target hit on 88.5% of trades
• It typically hit in about 17 days
• The bid-ask spread cost is small compared to the profit you bank

Compared to holding to expiration, this rule cut your call breach exposure roughly in half (21% vs 41%) and your put breach exposure in half too (6.6% vs 13.1%), while making more total money.

Don’t drop the target down to 25%. The 25% target wins more trades, but each win is so small that the bid-ask spread eats most of the profit. After 10 years you are barely up. The 50% target sits in the sweet spot of “big enough to actually pay you, fast enough to skip most trouble.”

Re-Enter on the Original 45-Day Cycle

When your profit target hits early, don’t rush back in. Wait for the original expiration date to pass, then put on the next strangle on the next available trading day.

In practice, this means spending about 28 of every 45 days in cash. That cash time is not wasted time. It is what limits your exposure to the next surprise move. The strategy is supposed to spend most of its time on the sidelines. That is a feature, not a bug.

Equal Delta Does Not Mean Equal Risk

This is the most subtle point, but the most important.

A 17-delta call and a 17-delta put look symmetric on paper. They are not. The call has less buffer, drift works against it, and it gets tested 3 times more often. The put has more buffer, drift works for it, but when it goes wrong it goes wrong big.

Some traders address this by selling the call at a slightly lower delta (12 to 15 delta) to widen the call-side buffer. Others buy a long out-of-the-money call as a tail hedge against runaway upside. Others skip the call leg entirely and just sell puts, since the put side carries the positive expected value.

The data does not say one of these is universally right. It just says: stop assuming both legs are the same risk. They are not.

FAQs

Q1: Why does the call side get tested so much more than the put side?

The simplest answer is that SPY tends to go up. Over the last 10 years, SPY finished higher about two-thirds of the time over any 45-day window. That gentle upward drift quietly pushes price toward the call strike, day after day, trade after trade. Combined with the call strike sitting about 5% above spot at entry (vs 6.5% below for the put), the call leg simply has less room to absorb normal market movement. This is not a temporary thing. It is how equity markets behave over long periods.

Q2: Does this mean the put side is safe?

Not at all. Puts get tested less often, but when they do, they tend to go much further past the strike. In our data, calls overshot their strike by 1.8% on average when breached. Puts undershot by 6.3% on average, with a single worst case of 25% during COVID. So the put side is a different kind of risk: rare, but big when it shows up. Position sizing should always assume a deep put breach is possible, even if it does not happen often.

Q3: Is a 50% profit target really better than holding to expiration?

In our 10-year sample, yes. The 50% target made about $62 per contract over the decade vs $55 holding to expiration. The breach exposure was much lower (21% vs 41% on calls, 7% vs 13% on puts). And the average time in the market was half. The reason is that most breach risk shows up in the second half of the trade, so by exiting early you collect the cleaner front-half profit and skip most of the trouble. That said, no exit rule is magic. The COVID trade got hit before any profit target had a chance to fire. What the 50% target does is reduce your average exposure across the dozens of normal trades over a decade.

Q4: Should I just sell puts and skip the call leg?

It is a reasonable question, and the data supports the logic. Independent backtests have shown that 45-day short SPY calls have generally lost money over time, while 45-day short SPY puts have made money. Our breach data agrees with that direction. The case for keeping the strangle is the diversification benefit. In our 61 trades, both legs were never breached at the same time. So selling both gives you a smoother return stream. The case for selling only puts is simplicity and a cleaner edge. The right answer depends on which one matters more to you.

Conclusion and Key Takeaways

The idea that 17-delta short strangles are balanced, two-sided trades does not hold up against 10 years of real SPY data. The call side carries more day-to-day breach risk than the put side. The right way to manage them is not the way most options education teaches.

A few patterns stand out:

• The call leg got breached 41% of the time when held to expiration. The put leg only 13%. That is a 3-to-1 ratio in favor of the call side.
• This pattern held across every exit rule we tested. With a 50% profit target, breach rates were 21% (call) vs 7% (put). With a 25% target, 13% vs 7%. Calls dominated puts in 7 out of 10 years.
• Closing trades early at a 50% profit target made the most total money over the decade ($62 per contract) compared to holding to expiration ($55) or using a 25% target ($23).
• The IV skew (puts costing about 1.5 times more than calls) is real, but it is pricing the size of the move when it happens, not the frequency. Calls breach often but barely. Puts breach rarely but deep.
• Most breach risk shows up in the back half of the trade, which is why early exits work so well.

Putting this together: the call side is where your day-to-day attention should go. The put side is where your tail-risk sizing decisions should go. The 50% profit target is your default exit rule. And spending most of every cycle in cash is the strategy working as designed.

This does not mean the strangle strategy is broken. It just means a clearer view of where the risk actually lives makes it easier to trade well.

Methodology note: All 61 trades were tested using real SPY options chains from January 2016 through March 2026, totaling 752,094 individual contract observations. Entries used the bid (what you would actually have collected). Exits used the ask (what you would actually have paid to close). Profit targets were measured on end-of-day prices; in real trading, GTC limit orders may fill intraday and slightly improve results. The full per-trade dataset is available on request.