The Implied Move and Strike Selection: Using IV to Set Targets

What Does Implied Volatility Tell You About How Far the Stock Might Move?

Implied volatility (IV) is the market's forecast of how much a stock will move over a given timeframe. You can translate IV into an expected move—the implied move—and use it to select strike prices that align with your volatility forecast. If IV suggests a 5% move but you expect 10%, you might buy OTM options further away than the market is pricing. Conversely, if IV is pricing a 10% move but you expect only 3%, you might sell ATM premium and profit from the excess IV. This article shows how to calculate implied move, interpret it, and use it to make smarter strike selections.

Quick definition: The implied move is the market's probabilistic expectation of how far a stock will move over a specified period, derived from IV using the Black-Scholes model or approximation formulas. A 30% IV with 30 days to expiration implies roughly a 5% move (approximately IV divided by the square root of 252 and multiplied by the square root of days). Larger implied moves suggest wider strike selection; smaller implied moves suggest tighter strikes.

Key takeaways

• Implied move ≈ IV × sqrt(days / 252): A 30% IV over 30 days suggests a 5.4% move; a 60% IV suggests a 10.8% move.
• ATM straddle value approximates implied move: A straddle costing as much as the expected move is fairly priced for the volatility environment.
• High IV environments widen the implied move: earnings, macro events, market crashes all spike IV and implied move. Select wider strikes.
• Low IV environments tighten the implied move: quiet markets have low IV and small expected moves. Tight strikes and spreads are better.
• Strike selection should match implied move: selling a 5% OTM call when the implied move is 10% is underpriced; selling when the implied move is 2% is overpriced.
• Mismatch between expected and implied move is the edge: if IV is 30% but you expect 50%, buy OTM options. If IV is 50% but you expect 20%, sell premium.
• Implied move compounds: moves on one day don't repeat daily; implied move is the 1-standard-deviation band over the full period.

Calculating Implied Move

The formula for annualized implied move is:

Implied move % = IV (as decimal)

To convert annualized IV to the move expected over N days:

Implied move % for N days = IV × sqrt(N / 252)

Example: Calculating implied move

Stock trading at $100, IV is 30%, 30 days to expiration.

Implied move = 0.30 × sqrt(30 / 252)
             = 0.30 × sqrt(0.119)
             = 0.30 × 0.345
             = 0.1035 or 10.35%

The market is implying a move of roughly 10.35% ($10.35) over the next 30 days, with a 68% confidence interval (one standard deviation) ranging from $89.65 to $110.35.

Example 2: Implied move for earnings (5 days out)

IV spikes to 60% (typical for earnings week) with 5 days to expiration.

Implied move = 0.60 × sqrt(5 / 252)
             = 0.60 × sqrt(0.0198)
             = 0.60 × 0.1407
             = 0.0844 or 8.44%

Despite the lower number of days, the 60% IV implies an 8.44% move. The market expects a large move compressed into five days.

Annualized IV conversion check:

The 60% IV for 5 days is not the same as "60% annualized IV." Rather, the option market is pricing 60% annualized IV for the next 5 days. If you annualize the 8.44% move over 5 days:

Annualized = 0.0844 × sqrt(252 / 5)
           = 0.0844 × sqrt(50.4)
           = 0.0844 × 7.1
           = 0.599 or 59.9% ≈ 60%

This confirms the calculation: 60% IV over 5 days equals an 8.44% move, which annualizes to 60%.

Using Straddle Value to Estimate Implied Move

A simpler way to think about implied move is through the lens of a straddle. A straddle is a long ATM call + long ATM put. If you buy a $100 straddle when the stock is at $100, you are betting on volatility—any move above or below the straddle's cost will be profitable at expiration.

The straddle value approximates the market's expected move:

Straddle value ≈ Implied move × Stock price

If the straddle costs $10 on a $100 stock, it implies a 10% move. If it costs $5, a 5% move.

Example: Straddle and implied move alignment

Stock at $100, 30 days to expiration, IV 30%, straddle (ATM $100 call + $100 put) costs $10.40 total.

Implied move = 10.4% / 100 = 10.4%

If the stock moves exactly 10.4% (to $110.40 or $89.60), the ITM leg of the straddle is worth $10.40 (or more, due to remaining time value). The straddle is at breakeven, fairly priced.

If the stock moves 20% (to $120), the ITM leg is worth $20+, and the straddle doubles its value. The straddle was underpriced—IV was too low.

If the stock moves only 5% (to $105), the ITM leg is worth $5, and the straddle loses $5.40. The straddle was overpriced—IV was too high.

This is why traders compare actual realized volatility (what the stock actually did) to implied volatility (what the options market priced in). The difference is the trading edge.

Strike Selection Using Implied Move

Once you know the implied move, you can select strikes intelligently:

Scenario: Stock at $100, implied move 10%, earnings in 5 days

The market expects the stock to land in the $90–$110 range with 68% confidence. Beyond that range (±10%), the probability drops significantly.

If you are bullish and expect the move to be up 10%+:

• Buy the $105 call (5% OTM): costs maybe $1.50, requires a 5% rally to be ATM at expiration. The implied move of 10% should push the stock past $105, so the option is well-positioned. This is buying slightly out of the implied move.
• Buy the $110 call (10% OTM): costs maybe $0.60, requires a 10% rally to be ATM. You are right on the edge of the implied move, so the odds are lower, but the leverage is higher.
• Buy the $115 call (15% OTM): costs maybe $0.20, requires a 15% rally. This is beyond the implied move, a lottery bet with high leverage but low probability.

If you are selling premium (neutral outlook):

• Sell the $95/$105 put spread: sell the $95 put (5% OTM) for $1.00, buy the $100 put (ATM) for $0.50, netting a $0.50 credit. The range $95–$105 is where the market expects the stock to trade (within one implied move). You are selling a spread that should stay profitable if the stock stays within the implied range.
• Sell the $90/$110 strangle: sell the $90 put and $110 call, each 10% OTM, collecting $0.50 total. This is selling outside the one-standard-deviation range; the odds of profit are >70%, but the reward per unit of risk is lower.

Volatility Smirk and Strike Selection

In real markets, IV is not uniform across strikes. A phenomenon called volatility smirk (or skew on equity indexes) causes OTM puts to have higher IV than ATM options, which have higher IV than OTM calls. This distorts the implied move and affects strike pricing.

Example: Volatility smirk on a stock

Stock at $100:

$95 put (5% OTM):   IV = 35%
$100 call (ATM):    IV = 30%
$105 call (5% OTM): IV = 28%

The $95 put is priced as if the stock will move 5% downside with 35% IV but only 5% upside with 28% IV. This reflects market fear: larger downside moves are more likely than upside moves (true in many crash scenarios). A sophisticated trader would note that downside puts are "overpriced" relative to upside calls, and might sell the $95 put while buying the $105 call to capture the smirk.

Beginners often ignore smirk and focus on the ATM IV, which is simpler but leaves money on the table.

IV to strike decision

Real-World Strike Selection Examples

Example 1: Earnings Strangle Using Implied Move

Tech stock trading at $200, earnings in 4 days, IV has spiked to 70%.

Implied move = 0.70 × sqrt(4 / 252)
             = 0.70 × 0.126
             = 8.8% or $17.60

The market expects a move of roughly $17.60. The 68% probability range is $182.40–$217.60.

You believe the move will be >10% (outside the implied range). You buy a $190 put and a $210 call (both roughly $8 OTM), paying $1.50 total for the straddle. If the stock moves $20 in either direction (to $180 or $220), you profit. The move must exceed the $17.60 implied move by enough to overcome the premium paid. If it does, you win big; if not, you lose.

Example 2: Covered Call Strike Using Implied Move

You own 100 shares of a dividend stock at $80, planning a one-month covered call. IV is 25%, 30 days to expiration.

Implied move = 0.25 × sqrt(30 / 252)
             = 0.25 × 0.345
             = 8.6% or $6.86

The market expects the stock to stay in the $73–$87 range. You believe the stock is stable and won't rally beyond $87.

You sell the $87 call (8.6% OTM, right at the edge of the implied move), collecting $0.60 in premium. Your breakeven is $79.40 (cost minus premium). If the stock stays below $87, you keep the premium. If it rallies past $87 and gets called away at $87, your profit is $7 per share (the call strike) plus $0.60 (premium) minus $80 (cost) = $7.60, or 9.5% return. This is a fair trade: you are being compensated for capping upside at the edge of the market's expected range.

Example 3: Bullish Bet Using Implied Move Expectancy

Stock at $150, IV 20%, 60 days to expiration (stock is quiet, IV is low).

Implied move = 0.20 × sqrt(60 / 252)
             = 0.20 × 0.488
             = 9.8% or $14.70

The market expects a small move, and options are cheap. You are bullish (conviction: 70%) and expect the stock to rally 15%+ (to $172.50), a move well above the implied 10%.

You buy the $155 call (3.3% OTM), paying $2.50. If the stock rallies to $165 in 30 days, the call is worth $10+, a 300% return. The key: the implied move is small ($14.70), so the $155 call is "cheap" in the context of your conviction. You are buying below-implied-move options.

Compare this to a high-IV scenario: stock at $150, IV 50%, 60 days out.

Implied move = 0.50 × sqrt(60 / 252)
             = 0.50 × 0.488
             = 24.4% or $36.60

The same $155 call (3.3% OTM) now costs $6.50 instead of $2.50. You are less inclined to buy because the option is "expensive" relative to the high implied move. In high-IV environments, buying OTM options is less attractive; selling premium becomes more attractive.

Common Mistakes

Mistake 1: Confusing Implied Move With Expected Move

Implied move is what the options market has priced in; expected move is what you believe will happen. If IV implies a 10% move and you expect 15%, buy options. If IV implies 15% and you expect 10%, sell. Many traders confuse these and end up selling options right before large moves (overconfidence that IV is too high) or buying options when IV is skyrocketing (paying peak prices).

Mistake 2: Using Annual IV Without Converting to Period

A trader looks at annual IV of 30% and thinks, "The stock will move 30% this month." But annual IV implies a 30% annualized move, which translates to only 2.5% per month. Failure to convert annualized IV to period IV leads to wildly inaccurate strike selections and over-levered positions.

Mistake 3: Ignoring Volatility Smirk

A trader sells a $95 put (3% OTM) and buys a $105 call (3% OTM) at the same distance from the stock, expecting symmetric risk. But if IV is smirked (puts have higher IV), the put is overpriced and the call is underpriced. The trader is taking an asymmetric bet: higher-IV short leg, lower-IV long leg. This is unknowingly buying a vega mismatch.

Mistake 4: Treating Implied Move as a Guarantee

One standard deviation (one implied move) covers 68% of outcomes. 32% of the time, the stock moves more than one implied move. A trader sells a straddle at the implied move as a 68% probability trade, not realizing that 32% of the time, the position loses money. Without proper position sizing and stop-losses, the 32% tail losses can wipe out the 68% wins.

Mistake 5: Changing Strike Selection Based on Yesterday's IV

IV changes daily. A trader calculates the implied move using yesterday's IV, then wakes up to find IV has spiked (earnings, macro news). The implied move has changed, but the trader has already locked in positions at yesterday's IV levels. Always calculate implied move using current IV, not historical IV.

FAQ

How do I find IV for a stock?

Most brokers display IV in the options chain (bid-ask columns show IV next to price). You can also use the underlying stock's put-call pairs to back-calculate IV. Free tools like OptionStrat.com or your broker's tools will show current IV.

Should I use the ATM IV or an average of all strikes?

Use the ATM IV. It is the most liquid strike and represents the "center" of the market's volatility forecast. OTM strikes often have different IVs (smirk) due to supply-demand imbalances. ATM IV is the cleanest input.

What if implied move is 10% but I expect 5%? Should I sell everything?

Not everything, but selling premium (short calls/puts) becomes attractive. If you expect a 5% move and the market is pricing 10%, you have an edge: the market is overestimating volatility. Sell ATM or slightly OTM options and profit from the decay of excess premium.

How does implied move change before and after earnings?

Pre-earnings, IV spikes, and implied move widens (maybe from 8% to 15%). Post-earnings, IV crashes, and implied move shrinks. If you are holding positions through earnings, you are exposed to IV collapse (vega loss) even if the stock moves as expected.

Can I use implied move for options more than 30 days out?

Yes. The formula works for any timeframe. A 6-month option with IV 25% implies a move of 0.25 × sqrt(180 / 252) = 0.25 × 0.845 = 21.1% over six months. The farther out, the larger the move implied.

What is the relationship between implied move and the delta of an OTM call?

Roughly, a call at the 1-standard-deviation move (implied move away from the current price) has a delta around 0.15–0.20, meaning about 15–20% probability of expiring ITM. An OTM call at 2 standard deviations (2× implied move) has delta around 0.02–0.05 and behaves like a lottery ticket.

Related concepts

• Price Movement vs. Time Decay: Gamma vs Theta
• Strike Distance From the Current Price
• Managing Different Expirations in Spreads
• Weekly vs. Monthly Premium Levels
• How Strike Affects Vega
• The Greeks: A Gentle Introduction

Summary

Implied volatility translates into an expected move using the formula IV × sqrt(N/252), where N is the number of days to expiration. This implied move is the market's one-standard-deviation forecast of how far the stock will move. Strike selection should align with your volatility forecast: if you expect moves larger than implied, buy OTM options further out; if you expect smaller moves, sell premium closer to the current price. The edge in options trading often comes from disagreeing with the market's volatility estimate: selling options when IV is too high, buying when IV is too low. Conversely, ignoring implied move and selecting strikes randomly forfeits this edge. A straddle's cost approximates the implied move; if a straddle costs 10% on a $100 stock, the market implies a 10% move. Earnings, macro events, and market crashes spike implied move and IV; quiet periods compress them. Always recalculate implied move using current IV before establishing positions, and expect that 32% of the time, reality will exceed the one-standard-deviation range.

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