How to choose a cash-secured put strike price

A cash-secured put combines a short put with enough cash to buy the underlying shares if assigned. The put buyer has the right to sell at the strike; the seller accepts the obligation to buy. The cash-secured put strategy guide covers the payoff. This page focuses on selecting the strike before opening the position.

Write down three prices before opening the option chain:

The effective basis is useful for comparing candidates, but it does not make the underlying safe. A $2 premium does not turn a $50 strike into a $48 limit order. If the stock falls to $30, the assigned shares still carry most of that decline.

• **Maximum acceptable purchase price:** the highest strike at which you would still want the shares
• **Effective share basis:** strike minus premium received, before fees, taxes, and later price changes
• **Stress purchase price:** the price you would be prepared to pay if the stock gaps well below the strike and assignment occurs

### 1. Decide whether you genuinely want the shares

Ask: “If this put is assigned tomorrow, can I own 100 shares per contract at the strike without changing my plan?” Include the company thesis, position size, cash reserve, portfolio concentration, and the possibility of a gap through the strike.

The Options Industry Council describes a cash-secured put writer as an investor who actually wants to acquire the underlying stock through assignment. Treat that as the first suitability test. If you only want premium and would resist owning the shares, a cash-secured put is not the right expression of the idea.

### 2. Set a maximum strike and a stress case

The maximum acceptable purchase price should be a decision about the shares, not a number backed into from the premium. Then write a stress case: for example, “I can still fund and hold 100 shares if the stock opens 25% below the strike.” This is not a forecast. It is a sizing test for an adverse path.

If the stress case makes the position too large, lower the strike, use fewer contracts, choose a different security, or skip the trade. Do not let a broker's buying-power figure substitute for a portfolio decision.

### 3. Use delta as a comparison, not a promise

Many traders screen put strikes by delta. A higher absolute put delta generally means greater price sensitivity and a higher modeled likelihood of finishing in the money under the model's assumptions. It is not a guaranteed assignment probability. Delta changes as price, time, implied volatility, dividends, and rates change. Read delta is not probability before turning a chain value into a forecast.

Use delta to compare strikes that already pass your purchase test:

Do not select “the 20-delta put” as a universal rule. First choose the price and share quantity you can own, then use delta to compare the remaining candidates.

### 4. Match expiration to the decision window

Expiration determines how long your cash is committed and how long the put can be assigned. A short-dated put can release cash quickly and allow frequent reassessment, but it creates more rolls, more execution decisions, and more exposure to a single event. A longer-dated put may pay more upfront, but it locks the purchase obligation for longer and leaves more time for the thesis to change.

Compare premium on a common time basis. A one-week premium annualized to look large is not directly comparable with a three-month outcome. Use how to choose an option expiration to make the calendar decision separately from the strike decision.

### 5. Check events and downside gaps

Earnings, regulatory decisions, product releases, mergers, and macro announcements can move a stock through several strikes before an order can be adjusted. Implied volatility may make the premium look attractive precisely because the event risk is high.

Before selling, record the next earnings date and known corporate actions. Decide whether you would still want the shares if the event produces a large gap below the strike. A premium is compensation for taking uncertainty; it is not a downside hedge.

### 6. Confirm the chain is tradable and the cash is reserved

Compare bid-ask spread, displayed size, open interest, volume, and minimum price increment. A theoretical strike is not useful if the order cannot fill at a reasonable price. Use a limit order and evaluate the expected fill rather than assuming the midpoint is executable.

Reserve the full potential share purchase amount, plus a buffer for fees, taxes, interest, and account changes. For one standard equity contract, the usual deliverable is 100 shares, but contract specifications can change after corporate actions. Confirm the multiplier and settlement terms with your broker and the relevant disclosure documents.

• a lower-absolute-delta OTM put usually offers a lower premium and a lower modeled assignment exposure
• a higher-absolute-delta put usually offers more premium while placing the strike closer to the current price
• an ITM put can offer a large credit, but much of that credit reflects intrinsic value and a high chance of buying the shares

Assume you would like to own a stock at $50 or less. The stock currently trades at $55, and each put expires on the same date. Ignore fees, taxes, dividends, and changes in the option price after entry.

| Strike | Premium | Cash reserved | Effective share basis | Premium yield on reserved cash | Loss at $40 after assignment | | ---: | ---: | ---: | ---: | ---: | ---: | | $55 | $4.00 | $5,500 | $51.00 | 7.3% | $1,100 | | $50 | $1.60 | $5,000 | $48.40 | 3.2% | $840 | | $45 | $0.55 | $4,500 | $44.45 | 1.2% | $445 |

The $55 put pays the most premium, but its strike exceeds the stated maximum acceptable purchase price. The $50 put fits the purchase plan and produces a $48.40 effective basis if assigned. The $45 put uses less cash and has a smaller loss at a $40 stock price, but it may expire worthless and collect only a small credit.

The last column is not a maximum-loss calculation. If the stock falls below $40, the assigned shares continue to lose value. It simply shows why a lower strike reduces the dollar amount at risk per contract while also reducing the chance of assignment and the premium received.

For each candidate, calculate:

1. **Premium income:** premium multiplied by the contract multiplier and number of contracts 2. **Premium yield:** premium divided by the cash base you explicitly choose 3. **Effective share basis:** strike minus premium per share if assigned 4. **Assigned stock outcome:** current stock price, strike, premium, and later share price under a stated scenario

For the $50 put sold at $1.60, the maximum option gain at expiration is $160 before costs. If assigned, the share basis is $48.40, but a later move to $40 produces an approximately $840 loss for 100 shares, before costs. The premium reduces the basis; it does not cap the stock loss.

Use cash-secured put maximum profit, loss, and breakeven to audit the arithmetic. Do not annualize the premium and call it a realized return when the put may be assigned or rolled.

Assignment can turn idle cash into a concentrated equity position. Add the potential shares to your existing exposure before placing the trade. Check sector weight, single-name concentration, correlation with other holdings, and the cash you may need for taxes or living expenses.

If owning 100 shares would exceed your limit, use fewer contracts or choose a lower strike that fits the portfolio. A “cash-secured” label only describes funding for the purchase obligation; it does not manage concentration risk.

If you are using a put as a possible entry, compare the effective basis with the price at which you would buy the shares directly. A short put can be assigned at a price above a later market price, and the premium may not compensate for the gap. Conversely, a put that expires worthless can leave you without shares during a rally.

Write down what happens in both branches:

The short put versus cash-secured put comparison explains why the cash reserve changes funding capacity but not the underlying market risk.

• **Expires worthless:** keep the premium and release the reserved cash
• **Assigned:** buy the shares at the strike, reduce the basis by the premium, and apply the stock exit plan

Do not force a trade because the chain displays an attractive yield. You can:

Skipping an unsuitable put is a complete decision. A cash-secured put is not a yield obligation that must be renewed every expiration cycle.

• wait for a better price or a more liquid expiration
• place a limit order only at a price that fits your worksheet
• choose a lower strike with a smaller premium
• use fewer contracts and keep the rest of the cash available
• buy the shares directly if owning them now is more important than collecting premium
• skip the position entirely

Re-evaluate from the current position, not from the original premium. If the stock rallies, compare closing the put, letting it expire, or accepting that the opportunity to buy at the strike may disappear. If the stock falls toward or below the strike, compare assignment, closing, or rolling with a new expiration and a new risk budget.

A roll is a new trade with a new strike, expiration, debit or credit, and assignment exposure. It does not erase the original result or guarantee a better effective basis. Rolling a cash-secured put versus assignment provides a separate decision framework.

• choosing the highest premium before stating the price at which you want the shares
• treating delta as a guaranteed probability of assignment
• comparing annualized yields across expirations with different event and gap risk
• ignoring the cash needed for 100 shares per contract
• using midpoint quotes as if they were executable fills
• overlooking earnings, corporate actions, or adjusted contract deliverables
• assuming the premium protects against a large decline
• selling multiple puts that would create an unwanted concentration if assigned
• rolling automatically instead of comparing a new trade with simply owning or not owning the shares

Record these fields before sending the order:

If the worksheet does not answer “Would I still want these shares at this strike after a gap lower?”, the put is not ready.

• underlying, current price, share thesis, and maximum acceptable purchase price
• stress purchase price and the number of shares you can fund and hold
• strike, moneyness, delta, expiration, premium, spread, open interest, and size
• cash reserved, buffer, premium yield, effective basis, and downside scenarios
• earnings, ex-dividend date, and corporate-action checks
• the response to a rally, a gap lower, early assignment, expiration, and a partial fill
• the stock exit rule if assigned and the date on which you will reassess