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Cash-secured put max profit, loss, and break-even
Calculate cash-secured put maximum profit, maximum loss, break-even and effective stock cost, reserved cash, multiplier, fees, and assignment outcomes.
Prepared by Mark · Primary sources below
Direct answer
A cash-secured put sells a put at strike K for premium C per share and reserves enough cash to accept the matching shares. Before costs and interest, maximum expiration profit is C, break-even and effective assigned stock cost are K - C, and maximum loss if the stock becomes worthless is K - C. Multiply by the contract multiplier and quantity. Cash security funds the obligation; it does not insure the acquired stock.
Separate premium from reserved cash
One standard short put at K = 50 can require 5,000 to buy 100 shares if assigned, subject to broker treatment. Receiving C = 1.75 produces 175 of option premium before costs.
Some brokers reserve the full strike value while others display cash net of premium. State which amount is used when calculating return on cash.
Maximum option profit is the opening premium
At or above K at expiration, the put can expire worthless and the gross strategy profit is C. The seller does not participate in stock upside beyond that amount because shares were never owned.
For K = 50 and C = 1.75, maximum profit is 1.75 per share or 175 per standard contract. Interest on collateral is a separate cash flow, not option premium.
Assignment creates an effective stock price
Below K, assignment purchases shares for 50 while the premium reduces economic cost to 48.25 before fees. That same K - C value is the expiration break-even.
If stock falls to zero, maximum loss is 48.25 per share or 4,825 for one standard contract. The position therefore exchanges limited premium for stock-like downside from the effective cost.
Assignment timing and missed upside matter
American-style puts can be assigned early. The cash must be available when stock is delivered, not only at the planned expiration date, and notification timing can leave additional market exposure.
If stock rallies far above K, the put seller keeps only C and may miss the stock move. That opportunity cost is not an option loss, but it matters when comparing the strategy with buying shares now.
Mark-to-market loss can arrive before break-even
Before expiration, a decline, higher IV, downside skew, remaining time, and wider markets can raise the put's repurchase price. The position can show a loss while spot remains above K - C.
Calculate the close transaction, assignment outcome, and post-assignment stock plan separately. A willingness to own shares does not make every strike or valuation acceptable.
Common questions
What is the cash-secured put maximum-loss formula?
Subtract the per-share premium received from the put strike, then multiply by contract multiplier and quantity and add relevant costs. This assumes the underlying can fall to zero and the put is assigned, leaving shares bought at K with an economic cost of K - C. Cash collateral makes that purchase fundable but does not reduce the market loss.
Is strike minus premium the tax cost basis?
It is a useful economic entry price and expiration break-even, but tax basis can depend on jurisdiction, assignment, commissions, holding periods, and account type. Keep the option premium, strike cash flow, and fees separately recorded and use broker statements or qualified tax advice rather than assuming the payoff formula controls reporting.
How much cash should be reserved?
The contractual purchase obligation is strike times multiplier times short-contract quantity, although the broker may display a net figure after premium or apply different treatment to cash equivalents and interest. The account also needs room for fees and adverse movement after assignment. Confirm actual buying-power rules rather than estimating from premium alone.
Is assignment always a good outcome for a cash-secured put?
No. Assignment may match the original stock-acquisition plan, but the company thesis, valuation, concentration, and market price can deteriorate before shares arrive. Buying at K is not attractive merely because it was acceptable at entry. Reassess the effective cost, current information, total share quantity, liquidity, and exit plan throughout the option term.
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