Options Basics

What exactly is an options contract?

An option is a contract between two parties. The buyer pays a premium for the right, not the obligation, to buy or sell a fixed quantity of an underlying asset at a fixed price on or before a fixed date. The seller receives that premium and accepts the matching obligation: if the buyer invokes the right, the seller must deliver or take delivery at the agreed price.

That structure makes an option a derivative. Its value is calculated from something else, most often a listed stock, an exchange-traded fund, or a stock index. Holding a call on a company is not holding the company. There is no vote, no dividend claim, and no share certificate, only a contractual claim priced off the share price.

There are exactly two contract types. A call option conveys the right to buy the underlying at the strike. A put option conveys the right to sell it at the strike. Every listed strategy, from a single long call to a four-leg condor, is some combination of those two contracts bought or sold in some ratio. The mirrored mechanics are laid out side by side in call option vs put option.

Listed options are standardized and centrally cleared. After a trade prints, the clearinghouse becomes the counterparty to both sides. That is why any qualifying buyer can face any qualifying seller, and why a position is closed by trading the same contract back rather than by negotiating an exit with the original counterparty.

What fields define a listed contract?

Six specifications identify a listed US equity option. Change any one and the result is a different security with its own quote, its own liquidity, and its own risk profile.

• Underlying. The stock, fund, or index the contract references.
• Type. Call or put. Nothing else exists at the contract level.
• Strike price. The fixed per-share price at which the holder can buy (call) or sell (put) the underlying on exercise. It does not move for the life of the contract, although corporate actions can create adjusted series with new terms.
• Expiration date. The deadline. Standard monthly equity options generally expire on the third Friday of the month, and weekly and daily listings fill in most other trading days on active names.
• Deliverable and contract multiplier. A standard US equity contract covers 100 shares, and the multiplier of 100 converts a per-share quote into cash.
• Exercise style. American-style contracts can be exercised on any business day through expiration, which covers most single-stock and ETF options. European-style contracts can be exercised only at expiration, which covers many cash-settled index options. The full contrast is in American-style option vs European-style option.

Convert each quote into cash before sizing the trade. A $4.25 premium costs $425 for one standard contract. With XYZ at $62.40 and a $60 strike, the underlying notional is $62.40 × 100 = $6,240, while exercise requires $60 × 100 = $6,000. Delta-equivalent exposure applies the option’s delta to the 100-share position. The $425 is the most the buyer can lose, the $6,000 is the cash exercise demands, and delta tells you how many shares the position trades like today.

How does a quoted premium decompose?

Every option premium has exactly two parts, and the split is arithmetic rather than opinion.

Intrinsic value = max(stock price - strike, $0) for a call Intrinsic value = max(strike - stock price, $0) for a put Extrinsic value = premium - intrinsic value

Intrinsic value is what the contract would be worth if exercised immediately. Extrinsic value is everything paid above that, and it prices time remaining, expected movement, interest rates, dividends, and order-book demand. The two are compared directly in intrinsic value vs extrinsic value.

A worked example, line by line

XYZ trades at $62.40. With 45 days to expiration, the 60-strike call is quoted $4.10 bid and $4.25 ask. A trader buys one contract at the ask.

The $425 premium is 6.81% of the $6,240 underlying notional. The $64.25 expiration breakeven is 2.96% above the current $62.40 stock price. Use those measures with delta exposure to connect the option quote to the size and target of the trade.

Now settle the contract at four different closing prices. At expiration extrinsic value is zero, so the contract is worth exactly its intrinsic value.

• XYZ closes at $68.00. Intrinsic value is $8.00 per share, so the contract is worth $800. Profit is $800 minus the $425 paid, or $375. The stock moved 9 percent and the position gained 88 percent.
• XYZ closes at $64.25. Intrinsic value is $4.25, the contract is worth $425, and profit is exactly zero. This is the breakeven by construction.
• XYZ closes unchanged at $62.40. Intrinsic value is still $2.40, so the contract is worth $240 and the loss is $185. That $185 is precisely the extrinsic value paid at entry, surrendered to the calendar.
• XYZ closes at $58.00. The call finishes out of the money, expires with no value, and the loss is the full $425.

The unchanged-stock case is the one to sit with. Nothing went wrong with the forecast. The stock simply did not move, and the buyer paid $185 for movement that never arrived.

How does moneyness sort the chain?

Moneyness is the comparison between a strike and the current stock price, and it places every contract in one of three states. A contract is in the money when exercising it today would capture value, at the money when the strike matches the stock price, and out of the money when exercise would capture nothing. Calls and puts mirror each other at every strike, a relationship set out in in the money vs out of the money.

Only in-the-money contracts hold intrinsic value. At-the-money and out-of-the-money contracts are entirely extrinsic value, which is why they can be cheap in dollars and still expire with nothing. Extrinsic value peaks at the strike nearest the stock, because that is where the final outcome is least settled.

Moneyness changes with every tick in the stock. A call that opens the session in the money can close it out of the money. Only the relationship at expiration decides settlement.

How do you read an option chain?

The option chain is the quote table that organizes every listed contract for one underlying by expiration and by strike. Calls conventionally sit on the left, strikes run down the center, and puts sit on the right, so both sides of the same price level can be compared in one row.

Here is one expiration of an illustrative chain with XYZ at $62.40, decomposed into the two components. Every ask price is split into intrinsic and extrinsic value using the formulas above.

Read the table in three steps. First, separate intrinsic value from the remaining premium. Second, compare strikes around the $62.40 stock price; this example places the largest extrinsic value at $62.50. Third, read $62.50 as the nearest-strike ATM label: the call is strictly $0.10 out of the money and the put is $0.10 in the money. The call and put extrinsic values match at each strike because this illustration carries no rates or dividends. On a live chain, interest on the strike lifts the call side, dividends lift the put side, and American exercise rights shift the pair again.

A real chain adds more columns. Bid and ask define the executable market, while the last trade can be minutes or days old and can sit outside the current quote. Volume counts contracts traded during the session and resets each morning. Open interest counts contracts still outstanding after the prior clearing cycle, so the intraday figure is last night’s count; today’s opening and closing trades land in tomorrow morning’s number.

What do exercise and assignment actually do?

Exercise is the action that invokes the contract right. A call holder who exercises buys 100 shares per contract at the strike. A put holder who exercises sells 100 shares per contract at the strike. Cash-settled products pay an exercise-settlement amount instead of moving shares. Exercising the 60 call from the worked example requires $6,000 of cash or margin buying power for the shares, which is a very different capital commitment from the $425 the contract cost.

Option assignment is the same event seen from the short side. The holder chooses; the writer does not. A broker submits the exercise notice to the Options Clearing Corporation, OCC randomly assigns it to a clearing member firm carrying a short position in that series, and the firm allocates it among its own short customers either randomly or first in, first out. Partial assignment is possible: a trader short 10 contracts can be assigned on 3 and still hold 7.

Two timing rules matter. First, an American-style writer can receive a notice on any business day the position is open, so assignment risk is continuous rather than an expiration-day event. Early exercise becomes rational mainly when remaining extrinsic value is small relative to a separate benefit, most commonly an in-the-money call just before an ex-dividend date. Second, at expiration the process is largely mechanical: under exercise by exception, OCC exercises contracts that finish at least $0.01 in the money for clearing members, subject to member discretion, broker cutoffs, account-capacity checks, and contrary instructions.

For a holder with a profitable position and time left, exercise is usually the worse of two exits. Exercising captures intrinsic value only. Selling the contract captures intrinsic value plus whatever extrinsic value remains, at the price the market is actually paying. In the worked example the trader bought at the $4.25 ask, so an exit sells into the $4.10 bid and collects $410, while exercising the same contract captures only the $240 of intrinsic value. The $170 gap is the $185 of extrinsic value that exercise discards, less the $15 the seller gives up crossing the $0.15 spread.

What does this look like on a live tape?

On a working screen, none of the above appears as formulas. It appears as a chain pane, a flow pane, and a positions blotter.

In the chain pane, a trader watches the bid and ask move independently for each strike and expiration, because each intersection of a strike and a date is a separately quoted security. The moment the stock trades through $62.50, the call that was at the money is in the money without anyone trading the contract, and as the stock keeps climbing the strike carrying the peak extrinsic value moves up the board behind it.

In the flow pane, executions show size, time, exchange, and fill price relative to the quote. At $4.25, a 600-contract print represents $255,000 of premium. With XYZ at $62.40, those standard contracts reference $3,744,000 of underlying notional and $3,600,000 of exercise cash at the $60 strike. Read the execution side, related legs, volume, and position changes together to identify the setup.

The next morning’s open interest shows the net change in outstanding contracts after clearing. If yesterday’s heavy volume shows up as a large increase, more contracts were opened than closed. A flat or lower count means closes matched or outnumbered opens. Opening and closing trades in the same session net against each other, so read the change as the total for that contract, and take each print’s direction from its execution side and related legs before calling the new positions bullish or bearish.

Into expiration, the same numbers turn into settlement mechanics. Open interest sitting at in-the-money strikes is inventory that can convert to stock, which is why a short position that looked comfortable on Friday afternoon can become 100 long or short shares per contract by Monday morning.

What do beginners get wrong, and why?

Reading the per-share quote as the dollars at stake. Multiply every quote by the contract multiplier. A $0.55 premium costs $55 per standard contract. Ten contracts cost $550 and represent 1,000 underlying units. At a $62.40 stock price, their underlying notional is $62,400; a $70 strike corresponds to $70,000 of exercise cash.

Confusing in the money with profitable. Measure profit against the premium paid; moneyness measures only intrinsic value against the strike. The 60 call that finishes at $62.40 is in the money and still loses $185, because $1.85 of the $4.25 paid was extrinsic value that expired.

Treating the strike as breakeven. Add the premium to the strike for a long call and subtract it for a long put. The strike is where intrinsic value begins; breakeven is where the payoff repays the premium. A trader who buys the 60 call needs $64.25, not $60.00.

Assuming a correct direction pays. Plan the size and timing of the move along with its direction. Extrinsic value decays every day and falls when implied volatility drops, so a move that is too small, too slow, or that follows a post-event volatility collapse can leave the position underwater while the stock is up.

Reading volume as new positioning. Compare volume with the next morning’s open interest. Volume counts every trade, including the ones that close and transfer existing contracts; open interest is the count of what remains open, published after the overnight clearing cycle. A jump in open interest after heavy volume marks new positions, and the print’s execution side shows their direction.

Assuming assignment only happens at expiration. Plan for assignment on any business day the short position is open, because American-style contracts allow it. Buying the short leg back is the only action that ends that exposure, and the deadline is the close of the session rather than the moment a holder files a notice: OCC processes closing transactions ahead of exercises and allocates the day’s notices after the close, so only positions still open at the end of the session can be assigned.

Assuming the deliverable is always 100 shares. Size from the contract specification, not the 100-share convention. Splits, mergers, and special dividends can produce adjusted series with a different deliverable or multiplier, and index products define their own multipliers.

What to learn next

Read the mechanics in the order the money moves. Start with options for the contract itself, then contract multiplier so every quote converts to cash reflexively. Move to option premium, then split it with intrinsic value and extrinsic value until the decomposition is automatic on any quote.

Next, learn the geography. Moneyness and its three states, in the money, at the money, and out of the money, map the whole board, and strike price plus expiration date are the two dials that place a contract on it. Convert any candidate into a required move with break-even price, and read its true scale from notional value rather than from premium.

Then learn how positions end. Exercise and option assignment are the two halves of the same event, and American-style option versus European-style option determines when that event can happen. Finish with the reading surfaces: option chain for contract selection and open interest for the positioning context behind it.

From there the next layer is pricing sensitivity. The Greeks describe how the premium responds to price, time, and volatility, and implied volatility explains why two contracts on the same stock and the same date can carry very different extrinsic value. Those concepts sit directly on top of the decomposition worked through here, and every one of them assumes the same conventions: premium per share, deliverable of 100, and extrinsic value that reaches zero at the deadline.