Short Options

The short side is the mirror image of the long side. Three facts from the outline: the writer earns the premium, faces a large risk the outline calls unlimited, and can take a loss that exceeds the premium received. All three come from the writer holding an obligation, not a right. The writer cannot walk away, so the downside stays open.

Earn the Premium: The Maximum Gain

The writer receives the premium at the trade and keeps it no matter what happens.

• That premium is the writer's maximum possible gain on the position. There is no way to make more than the premium collected.
• The best case is that the option expires worthless (out-of-the-money), the buyer never exercises, and the writer simply pockets the full premium. This is why writers sell options: to collect premium as income, betting the option will not move enough against them.
• The writer keeps the premium whether or not the option is assigned. Even when assignment happens and the writer takes a loss, the premium already collected offsets part of it.

Unlike the buyer, the writer must post a performance bond (margin). The writer's future obligation is open-ended and must be collateralized, so the exchange requires a good-faith deposit that the buyer never has to make.

Think of it this way: writing an option is like selling an insurance policy. You collect the premium up front and keep it. If nothing goes wrong, that premium is pure profit. But if the event you insured against happens, you owe the claim, and the payout can dwarf the premium you took in. That is why the insurer (the writer) has to keep money on deposit and the customer (the buyer) does not.

Unlimited Risk: The Naked Short Call

The outline states the short side's risk as "unlimited," and the case that makes it literally unlimited is the naked (uncovered) short call.

• If assigned, the call writer must deliver a short futures position at the strike while the future has risen with no ceiling. The loss grows without bound as the price climbs.
• This is the exact mirror of the long call's unlimited profit: whatever the long call gains on a runaway rise, the short call loses. The writer's small, fixed premium is dwarfed by an open-ended payout.
• Because the exposure has no upper limit, a naked short call is the highest-risk plain option position on this exam. It is the position the outline is pointing at when it labels the short side "unlimited risk."

Exam Tip: Gotchas

• Only the naked short call is truly unlimited. The future has no price ceiling, so an assigned call writer's loss can climb without bound. This is the mirror of the long call's unlimited profit.

Loss May Far Exceed the Premium: The Short Put Is Bounded

For any short option, the outline's third fact holds: the loss can exceed the premium received. But be precise about the word "unlimited," because the short put is where the exam sets its trap.

• The premium is a fixed, small credit. The payout on assignment can be many times larger, so the writer's downside is not capped at the premium the way the buyer's is.
• A naked short put has a large but bounded loss, not a literally unlimited one. The underlying future can fall only to zero, so the writer's maximum loss is the strike minus the premium received.
• The short put still loses far more than its premium in a bad move, but the floor is defined. So the accurate reading of the outline is: the short call is the unlimited-risk case (no price ceiling), while the short put is the large-but-bounded case (strike minus premium).

For the calculation-minded, a naked short put's worst case is the same distance the buyer of that put could gain: $\text{strike} - \text{premium}$, reached only if the future goes to zero.

Memory Aid: A short call has no ceiling, so its risk climbs without a lid; a short put has a floor at zero, so its risk stops at the strike minus premium. Lead with the call for "unlimited," but never call a short put unlimited.

Exam Tip: Gotchas

• A short put is bounded, not unlimited. Its maximum loss is the strike minus the premium, reached only if the future falls to zero. Calling a short put "unlimited risk" is a common distractor; only the short call earns that label.
• The writer's gain is capped and the loss is open, the exact reverse of the buyer. The writer keeps the premium either way (the maximum gain) and posts margin; the buyer pays the premium in full up front, posts none, and can lose no more than it. Do not flip which side carries the margin.

Long Versus Short: The Full Picture

With both sides taught, the outline's six facts line up in one table. Read each row as a mirror: what the buyer risks, the writer can win; what the buyer can win, the writer risks.

The one-line hook to carry into the strategy units: the buyer trades a known, small loss for a large, uncertain gain; the writer trades a large, uncertain loss for a known, small gain. Every plain-option fact in this unit is a restatement of that asymmetry, and every strategy ahead is a way to reshape it:

• Hedging uses the limited-risk long side as insurance on a futures position.
• Speculating expresses a directional view with defined risk, or harvests premium and accepts the open-ended risk.
• Spreading pairs a long and a short option to cap both the maximum profit and the maximum loss.

Memory Aid: Buyer = Bounded loss, Big upside. Writer = the reverse: small, capped gain and the open-ended risk. The buyer paid for the good side of the trade; the writer sold it.

Exam Tip: Gotchas

• The four maximums are a matched set, so learn them as mirrors. Buyer maximum loss is the premium (capped); writer maximum gain is the premium (capped). Buyer maximum gain runs large (call unlimited); writer maximum loss runs large (call unlimited). A question that swaps any one of these across sides is testing whether you memorized isolated facts or the underlying asymmetry.