Long Put: how the position works

The right to sell the underlying at a fixed strike until expiry. It is the mirror of the long call with one asymmetry that matters: the underlying can only fall to zero, so the profit is large but bounded, whereas a call's is not. It is also the building block of most hedges, because it is the only position that pays more precisely when everything else you own is paying less.

Market view: Bearish — directional, or a hedge
Opened for: Debit
Maximum profit: K − premium paid, reached only if the underlying goes to zero. Large but bounded, unlike a long call.
Maximum loss: The premium paid, realised at or above the strike at expiry.
Breakeven: K − premium paid, at expiry.

How it is built

Buy 1 put at strike K, expiring at T

All figures above are quoted per share and settle at expiry. A standard equity option covers 100 shares, so multiply by 100 for a single contract.

Before expiry: the Greeks

Negative delta, between 0 and −1, near −0.5 at the money. Long gamma, so the position gets shorter as the underlying falls and the move compounds. Long vega, which is why puts are expensive precisely when people want them: volatility and falling prices arrive together, so the hedge reprices upward as the risk it covers materialises. Short theta.

When to use it

To express a bearish view with a loss you cap in advance rather than the unbounded one a short stock position carries, or to insure a holding you do not want to sell — for tax reasons, or because you still like it long term. As a hedge its cost is the honest price of the protection, not a fee to be minimised into uselessness.

What goes wrong

The premium is a real, recurring cost. Rolling protective puts quarterly can consume a large share of a portfolio's return in a market that simply drifts up.
Puts are structurally expensive. Equity index skew prices downside strikes above the equivalent upside strike, so you routinely pay more than a symmetric model implies.
Volatility can fall while the underlying does too. A slow grind down with implied volatility collapsing can leave a put barely profitable despite the direction being right.

A worked example

QQQ trading at 500. Buy the 490 put, 60 days to expiry, for 9.40.

Debit paid: $9.40 per share — $940 for one contract
Breakeven at expiry: $480.60 (490 − 9.40)
Loss if QQQ finishes at or above 490: $940, the whole premium
Profit if QQQ finishes at 450: $3,060 ((490 − 450 − 9.40) × 100)

Commissions, exchange fees, financing and the bid/ask spread are excluded. On a multi-leg position the spread is usually the largest of these.

Common questions

Is a long put better than shorting the stock?

It has a different risk shape. The put caps your loss at the premium and needs no borrow, while a short sale has unbounded loss, pays borrow costs and can be recalled. The put pays for that safety with time decay, so the short is cheaper to hold if the fall is slow.

How far out should a protective put be?

Longer expiries cost more in absolute terms but less per day, because time value decays fastest at the end. If the protection is meant to be permanent, longer-dated puts rolled less often usually cost less per unit of cover than short-dated ones rolled constantly.

Related strategies

Educational only. This page explains how a structure behaves; it is not a recommendation to trade it. Options and futures carry substantial risk, and short and leveraged positions can lose more than the amount originally invested.