Model and input conventions
The per-unit expression is terminal underlying price minus acquisition price, plus max(put strike − terminal price, 0), minus put premium. Multiply this amount by the protected underlying quantity and subtract total fixed costs. Below the put strike, losses on the held underlying are offset by the put’s growing intrinsic payoff. Above the strike, the put expires without intrinsic value and the holding retains its upside slope.
Worked numerical example
Suppose the underlying was purchased at 100 and a 90-strike put costs 3. With one unit and no fees, the combined worst expiry P&L is −13. A collapse to zero and an expiry at 90 produce the same result in this model. At 110, profit is 7. Break-even is 103 because the final holding value must also recover the option premium.
Read the scenario table
The table shows stock P&L and put payoff separately, making their offset below the strike easy to verify. A blank best-P&L metric means the mathematical upside has no finite ceiling, not that every scenario makes money. Enter the actual historical acquisition price if measuring a complete holding; use a current valuation only when deliberately measuring incremental performance from a new starting point.
Where the model stops
The protection is modeled only for the stated expiry and equal underlying quantities. It does not cover a future date after the put expires, a different token, an impaired settlement counterparty or liquidation of financed collateral before settlement. Early exercise, premium financing and taxes are absent. The option’s pre-expiry resale value may differ substantially from the terminal intrinsic value shown here.