Strike Price and Expiration

Introduction

Every option ever written is pinned down by just two numbers: which price it deals at, and by when. The first is the strike price; the second is the expiration date. Choose those two coordinates and you have specified a contract exactly — a £50 call expiring in March is a completely different instrument from a £55 call expiring in June, even on the same stock.

Understanding these two coordinates is the foundation for everything else in options: moneyness, premium, the Greeks and every strategy are all built on top of which strike and how much time. This lesson takes them one at a time, shows how they sit together on an options chain, and explains how the pair of choices shapes what you pay and how likely you are to profit.

Quick Definition

The strike price is the fixed price at which an option lets its holder buy (a call) or sell (a put) the underlying. The expiration date is the deadline after which that right ends. Together they define the contract.

Neither number is the premium — the premium is the separate, market-set price you pay to own the option. The strike and expiration are the terms of the contract; the premium is its cost.

The Strike Price

The strike is the price written into the contract. A £50 call gives its holder the right to buy the underlying at £50; a £50 put gives the right to sell at £50 — no matter where the market price wanders. The strike is fixed for the life of the option and never moves.

Exchanges list a whole ladder of strikes around the current share price, spaced at regular intervals (say every £1, £2.50 or £5 depending on the stock's price). That ladder is what lets you choose how aggressive your option is:

• A call struck below the current price is already valuable and behaves much like the shares.
• A call struck far above it is cheap but needs a big rise to pay off.

Choosing the strike is therefore choosing your trade-off between cost and the size of move you need — the subject of the next lesson, moneyness.

The Expiration Date

The expiration date is the option's deadline. Up to that date, the holder may exercise their right; after it, the option simply ceases to exist. At expiration one of two things happens:

• If the option holds intrinsic value (a call whose strike is below the market price, or a put whose strike is above it), it is exercised or cash-settled for that value.
• If it does not, it expires worthless, and the holder loses the premium they paid.

Time is the option buyer's enemy and the seller's friend. With each day that passes, an option has less time left for the underlying to move favourably, so its extrinsic (time) value bleeds away — a process called time decay, covered in the theta lesson. This is why the same strike costs more with more time on the clock.

The Options Chain: Two Coordinates At Once

Brokers present options as a chain — a grid with expiration dates across the top and strike prices down the side. Every cell is one contract. Picking a trade means choosing one column (an expiration) and one row (a strike).

The Expiration Calendar: Weeklies, Monthlies and Quarterlies

Not all expirations are equal in how much time they carry:

• Monthly options are the traditional contracts, historically settling on the third Friday of the month. They remain the most heavily traded.
• Weekly options ("weeklies") expire every week. They are cheaper and shorter-lived, popular for near-term views and events — but they decay fast, because so little time separates them from expiry.
• Quarterly and month-end expirations exist too on major indices and large stocks, widening the menu further.

Mechanically, a weekly and a monthly behave identically; they differ only in the amount of time they carry, which is exactly what changes the premium and the pace of time decay.

LEAPS: Options With A Long Horizon

At the far end of the calendar sit LEAPS — Long-Term Equity AnticiPation Securities — simply options with long-dated expirations, often one to three years out. Because they carry so much time value, two things follow: their price moves more closely with the underlying (they behave a little more like owning the shares), and their day-to-day time decay is slow. That makes LEAPS a tool for longer-horizon directional views, or as a lower-capital, defined-risk stand-in for holding stock over years rather than weeks.

How Strike And Expiration Work Together

The two coordinates are not independent choices — they trade off against each other to set both the cost of the option and its probability of paying off:

• A strike close to the current price costs more but is likelier to finish in-the-money; a strike far away is cheap but needs a big move.
• A longer expiration costs more but gives the underlying more time to reach your strike; a shorter one is cheaper but far less forgiving of bad timing.

Buy a cheap, far-out strike on a short-dated option and you have a lottery ticket: low cost, low odds. Buy a near-the-money strike far in the future and you have paid up for time and probability. Every option sits somewhere on that grid, and choosing well means matching the strike and expiration to the size and timing of the move you actually expect.

Risks & Considerations

• A strike is not a target price you are guaranteed to reach — it is merely the price the contract deals at. The underlying must actually get there to pay off.
• Nearer expirations decay faster. A weekly option can lose value alarmingly quickly if the move does not come almost immediately.
• Longer expirations cost more up front and tie up capital for longer, even though they decay more slowly.
• The wrong pairing wastes money: a far-out strike on a short-dated option rarely pays; an expensive near-dated, near-the-money option can be dear for a modest move.
• Corporate actions (splits, special dividends) can adjust strikes and contract terms — always read the contract specification.

Common Misconceptions

• "The strike is what I pay for the option." No — that is the premium. The strike is the price at which the option lets you deal in the underlying.
• "A longer expiration is always safer." It decays more slowly and gives more time, but it also costs more and can still expire worthless if the move never comes.
• "Weeklies are just cheaper monthlies." They are cheaper because they carry less time — which also makes them decay much faster and far less forgiving.
• "LEAPS can't lose much because they're long-dated." They still carry real risk; a long-dated option can lose most of its value if the underlying moves the wrong way or stalls.

Real-World Application

Two investors share the same bullish view on a £50 stock. The first buys a £52 call expiring this Friday for £0.40 — a cheap, near-term bet that pays handsomely if the stock jumps in days, but expires worthless if the move slips even a week. The second buys a £50 call expiring in eighteen months (a LEAPS) for £8 — far more expensive, but it moves closely with the shares, decays slowly, and gives the thesis over a year to play out. Same direction, same stock, radically different instruments — because they chose different points on the strike-and-expiration grid. The lesson is that "being right" on an option means being right about the price, the size of the move and its timing, and the strike and expiration are how you encode all three.

Key Takeaways

• Every option is defined by two coordinates: the strike price (the fixed price it deals at) and the expiration date (the deadline after which its rights end).
• The strike is not the premium; exchanges list a ladder of strikes so you can choose how aggressive the option is.
• At expiration an option is exercised/settled if it holds intrinsic value, or expires worthless if it does not.
• An options chain is a grid of strikes and expirations; picking a contract means choosing one of each. Expirations range from weeklies to monthlies to long-dated LEAPS.
• Strike and expiration trade off to set both the premium and the odds — matching them to the expected size and timing of the move is the heart of choosing an option.