Put Option¶
A put option is a standardized contract giving its buyer the right — but not the obligation — to sell 100 shares of an underlying stock at a fixed strike price on or before the expiration date. The buyer pays a premium upfront; the seller collects that premium and accepts the obligation to purchase the shares at the strike if assigned. Puts gain value as the underlying falls, making them the core instrument for bearish speculation and portfolio protection.
HOW IT WORKS¶
At expiration, the buyer's payoff per share equals max(0, Strike − Stock Price) − Premium Paid, with breakeven at Strike − Premium Paid and maximum profit capped at Strike − Premium (since a stock cannot fall below zero). Before expiration, a put's price splits into intrinsic value (max(0, Strike − Stock Price)) and extrinsic value, which erodes through theta decay as expiration approaches and expands with rising implied volatility. Put delta is negative — an at-the-money put carries a delta near −0.50 — and because equity markets price crash risk heavily, puts trade richer than equidistant calls, a phenomenon known as volatility skew.
Common applications include:
- Portfolio hedging — buying index puts to insure an equity position against drawdowns
- Bearish speculation — long puts provide defined-risk short exposure with no borrow cost or short-squeeze risk
- Income generation — selling cash-secured puts collects premium in exchange for an obligation to buy shares at a lower price
- Spread construction — puts combine into bear put spreads, iron condors, and collars
IN TAPEBOARD¶
In the Tapeboard terminal, put options appear in the options chain with negative delta values and are filterable by strike, expiration, open interest, and implied volatility. The payoff diagram tool plots breakeven and max-profit levels automatically when a long or short put leg is added to a position. Use the Greeks panel to monitor theta decay in real time and the IV percentile indicator to assess whether a put's extrinsic value is historically elevated before entering a hedge or speculative position.