Definition
A protective put is the options equivalent of buying an insurance policy on a stock position. The investor owns shares of a stock and pays a premium to purchase a put option that grants the right — but not the obligation — to sell those shares at a specified strike price before expiration. If the stock collapses, the put can be exercised (or sold for a profit) to offset losses; if the stock rises, the put expires worthless and the only cost is the premium.
Strike selection is the key design choice. An at-the-money put offers near-complete protection but costs the most. An out-of-the-money put functions like a high-deductible policy: cheaper to carry, but only kicks in after a meaningful decline. Either way, the protection extends only from the strike downward — there is no floor below the strike's protective range that the put fails to cover.
When the put is purchased simultaneously with the underlying shares (rather than added to an existing position), the structure is sometimes called a married put. Mechanically the two are identical.
Why it matters
When the cost is worth it
Protective puts are not free, and over long horizons their drag on returns is significant. A useful framing: ask whether you would willingly pay the same premium amount, every quarter, for the next five years, to keep this position. If the answer is yes, the position likely warrants ongoing hedging — perhaps it represents concentrated wealth, employer stock, or capital you simply cannot afford to lose. If the answer is no, you are paying for peace of mind on a position that does not actually need protecting, and the cumulative cost will quietly compound against you.