What Are Options? Calls and Puts Explained

The Right vs Obligation Asymmetry

The word "option" is used deliberately. When you buy an option contract, you are buying a choice — specifically, the right to buy or sell 100 shares of a stock at a fixed price on or before a specific date. You are not obligated to do anything. If the option is not beneficial to exercise, you simply let it expire and lose only the amount you paid for it. This defined, capped downside is the most important property of being an option buyer.

The person on the other side of your trade — the option seller, or writer — has accepted the opposite deal. They received your premium payment, but in exchange they have taken on an obligation: if you choose to exercise your right, they must fulfil it. A call writer must sell you 100 shares at the agreed price, regardless of where the stock is trading. A put writer must buy 100 shares from you at the agreed price, regardless of where the stock has fallen. The seller's risk is asymmetric: they collected a fixed premium, but their potential loss can far exceed it.

One standard options contract in the US covers exactly 100 shares of the underlying stock. This is why option premiums are quoted per share but multiplied by 100 for the total cost. An option quoted at $3.50 costs $350 total ($3.50 × 100 shares). This multiplier creates significant leverage: $350 controls a position that might represent $20,000 worth of stock. That leverage amplifies both gains and losses — it is one of the most misunderstood aspects of options for beginners, who see "cheap" $50 options and underestimate what they represent in terms of underlying exposure.

Options were not always accessible to retail investors. Until the mid-2000s, they required specialised brokerage accounts, margin approval, and significant minimum balances. The rise of commission-free platforms like Robinhood (launched 2013, added options 2018) and Tastyworks (2017) democratised access dramatically. By 2021, options trading volume in the US was exceeding stock trading volume on many days, driven largely by retail speculation on single-stock options — particularly in meme stocks like GameStop (GME) and AMC. The January 2021 GME short squeeze was fundamentally a story about options: retail traders bought huge numbers of out-of-the-money call options, forcing market makers who sold those calls to buy GME shares as a hedge, which pushed the price up, which made more calls profitable, which triggered more hedging. Understanding that feedback loop requires understanding what options are and how dealers manage their risk.

Calls, Puts, and How the Payoff Works

There are exactly two types of options contracts: calls and puts. Everything else in options trading is a combination or variation of these two instruments. Understanding their individual payoff structures is the prerequisite for understanding every strategy, spread, or multi-leg position you will encounter.

Call Options: The Right to Buy

A call option gives the buyer the right to purchase 100 shares of the underlying stock at the strike price, at any time before the expiry date. Calls are directional bets that the stock will rise above the strike price. The payoff is simple: at expiry, if the stock is above the strike, the call has intrinsic value equal to (stock price − strike price) × 100. If the stock is at or below the strike, the call expires worthless.

Consider a concrete example: Apple (AAPL) is trading at $190 on January 1. You buy one call option with a $200 strike price expiring in 60 days, paying $4 in premium ($400 total). For this trade to profit at expiry, Apple must close above $204 (your break-even: $200 strike + $4 premium). If Apple rises to $220, your call is worth $20 per share ($2,000 total) — a $1,600 profit on a $400 investment, a 400% return. If Apple rises only to $198, the call expires worthless and you lose your $400. If Apple rises to $202, the call is worth $2 but you paid $4 — you lose $200 (50% of the premium). The asymmetry is stark: your maximum loss is $400 no matter what Apple does, but your gain scales directly with how far the stock moves above the strike.

Put Options: The Right to Sell

A put option gives the buyer the right to sell 100 shares at the strike price before expiry. Puts profit when the stock falls below the strike. They serve two purposes: speculation (betting a stock will decline) and hedging (protecting shares you already own from a drop). The put payoff at expiry is (strike price − stock price) × 100, if positive. If the stock is at or above the strike at expiry, the put expires worthless.

Example: Tesla (TSLA) is at $250. You own 500 shares (worth $125,000) and are worried about a near-term decline. You buy 5 put options at a $230 strike expiring in 45 days, paying $6 each ($3,000 total). If Tesla falls to $190, each put is worth $40 ($4,000 per contract, $20,000 for 5 contracts) — almost fully offsetting the $30,000 decline in your shares ($60/share × 500 shares from $250 to $190 = $30,000 loss, minus $20,000 put gain = net $10,000 loss instead of $30,000). Your $3,000 in put premiums bought $20,000 of downside protection. If Tesla rises to $280, your puts expire worthless and you lose the $3,000 premium — but your shares gained $15,000. The put was insurance: you paid a cost for protection that hopefully you don't need.

The payoff diagrams above illustrate the buyer's perspective at expiry. Both a long call and long put have identical structural properties: maximum loss is limited to the premium paid (the flat horizontal loss line); gain is unlimited for calls (stock can rise indefinitely) or large for puts (stock can fall to zero but not below). The break-even point — where the diagonal profit line crosses the x-axis — is always strike plus premium for calls, and strike minus premium for puts. This is the price level the stock must reach at expiry for the trade to be at exactly zero, covering the premium cost.

Moneyness, Buyers vs Sellers, and When to Use Options

Three terms describe the relationship between an option's strike price and the current stock price, collectively called moneyness. Understanding moneyness helps you interpret pricing, choose strike prices intelligently, and understand why options have the probabilities they do.

ITM, ATM, and OTM

An option is in the money (ITM) when it has intrinsic value based solely on the strike-to-stock relationship. For a call: the stock price is above the strike (you could theoretically buy at the strike and immediately sell for more). For a put: the stock price is below the strike (you could theoretically buy shares in the market and exercise the put to sell at the higher strike). An at the money (ATM) option has a strike equal to (or very close to) the current stock price — maximum time value, zero intrinsic value. An out of the money (OTM) option has no intrinsic value: the stock has not yet moved to make it exercisable profitably.

OTM options are cheaper but have lower probability of expiring with value. ITM options cost more (they already have intrinsic value) but have higher probability of retaining value. ATM options are where time value (the extra premium you pay for the possibility that the option might become valuable before expiry) is at its maximum. This relationship between moneyness and pricing is the core of options valuation — the Black-Scholes model essentially prices options by calculating the probability that they will expire in the money, discounted to present value.

Four Basic Positions and When to Use Them

Every options position is a variation of four fundamental trades: long call (buy a call), short call (sell a call), long put (buy a put), short put (sell a put). Combining these creates spreads, straddles, condors, and other multi-leg strategies. But first, the basics: buy calls when you expect a stock to rise significantly above the strike before expiry. Buy puts when you expect a decline, or when you want to hedge existing shares. Sell calls when you expect the stock to stay flat or decline (and are willing to cap your upside on shares you own — a covered call). Sell puts when you want to generate income on a stock you would be willing to buy at the strike price if it falls.

The critical warning for beginners concerns the selling side. Selling naked calls — calls without owning the underlying shares — exposes you to theoretically unlimited loss if the stock rises. The January 2021 GameStop squeeze was a visceral demonstration: traders who had sold GME calls at $20 or $30 strikes faced catastrophic losses as the stock hit $483 intraday on January 28. Some retail traders and at least one hedge fund (Melvin Capital, which held substantial short positions) suffered multi-billion-dollar losses. Selling naked options requires specific broker approval for good reason: the risk profile is the opposite of buying — capped gain, uncapped loss.

Options are used across the entire spectrum of market participants, from cautious portfolio hedgers to aggressive speculators. A pension fund buying protective puts on the S&P 500 before an earnings season is using the exact same instrument as a retail trader buying NVDA calls ahead of a GPU announcement — the economics are fundamentally identical, just the purpose differs. The instrument is neutral; it is the strategy, position size, and risk management that determine whether options are a conservative hedging tool or a speculative vehicle. The articles that follow build on this foundation to explain how options are priced, how time decay erodes their value, and how professional traders structure positions to express views with precisely defined risk.