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Call options explained: From opening trade to expiration
Yahia Barakah · Personal finance writer
Fri, August 7, 2026 at 7:56 PM GMT+3 18 min read
A call option contract offers its buyer and seller two different roles. The call buyer pays a fee up front for the right to buy shares at a set price, called the strike price, before the contract expires. The call seller, also known as the writer, collects that fee and takes on the obligation to deliver the shares at the set price if the buyer exercises their right.
At expiration, the call buyer comes out ahead only if the stock rises above the strike price by more than the fee paid. The call writer generally wants the stock to finish at or below the strike price, so they keep the full premium collected.
Let's follow an Nvidia call option through its entire life cycle to see exactly what both sides agree to, what they may gain, and what they risk losing.
Read more: What are stock options, and how do they work?
What is a call option?
A call option is a contract that gives its buyer the right, but not the obligation, to buy a stock or an underlying asset at a set price, called the strike price, before the contract expires.
The call buyer's right
Buying a call means paying a per-share fee up front, called the premium, for the choice to buy an underlying asset at the strike price any time before expiration. Standard stock calls cover 100 shares per contract, so a $5-per-share premium translates to $500 for the whole contract.
The buyer decides whether that right is worth using. If the stock never rises enough to make it worthwhile, the buyer can simply let the contract expire, losing only the premium they already paid, which is the most the buyer can lose on the trade.
The call seller's obligation
Selling a call flips that arrangement. The seller collects the premium right away but takes on an obligation to sell shares at the strike price if the buyer uses their right, or exercises the contract, no matter how much higher the stock has climbed by then.
The cost of fulfilling that obligation depends on whether the seller already owns the shares in question. A seller who owns the shares can simply hand them over. They give up any gain the stock has made above the strike price, but they keep the premium they collected.
A seller who doesn't own the shares still has to deliver 100 shares at the strike price. Calls typically get exercised when the stock is trading above the strike. The seller then ends up buying shares at the higher market price, only to hand them over at the lower strike price, losing the difference.
A call's life cycle in 5 steps
A call goes through a handful of stages, from the trade that opens it to the moment it closes, gets exercised, or expires. To understand each stage, let's take one contract from Nvidia's options chain on AlphaSpace by Yahoo Finance.
Explore options contracts with AlphaSpace
Nvidia's stock was trading at $212.26 at the time, with nearby strike prices spaced just $2.50 apart in the middle column. The chain displayed calls to the left side and puts to the right.
The two strikes right above the current price were at $212.50 and $215, with the $215 call showing an $8.20 ask and $8.30 bid. Here's what that call's life cycle looks like.
Read more: How to read an options chain
1. The buyer and seller open the trade
A buyer places an order to buy a call, and a seller (or writer) places an order to sell one, naming the same strike price and expiration date.
A buyer looking to trade right away would pay near the $8.30 ask, or $830 for the full contract. A seller looking to trade right away would accept near the $8.20 bid, or $820. Once a buyer and seller agree, the trade settles at the matched price.
After the trade settles, the Options Clearing Corporation (OCC), the clearinghouse behind every listed option trade, steps in as the counterparty to both sides. It guarantees that the buyer and seller each get what they're owed, no matter what the other side does later.
2. The call's value moves with the market
After the trade opens, the call's premium continues moving. Nvidia's stock price is among the main drivers. As the stock climbs, the call's value tends to climb with it, since the right to buy at $215 becomes more valuable the higher Nvidia's stock goes above that price. A drop in Nvidia pulls the call's value down the same way.
The market's expectation for how much Nvidia may move, known as implied volatility (IV), also affects the call's price. A wider expected swing gives the call more room to pay off without increasing the buyer's maximum loss, which remains capped at the premium already paid. That's why bigger expected swings tend to raise a call's price, even before the stock itself moves.
Time plays a role too. Assuming all else is equal, a call with only a day or two left is typically worth less than the same call with plenty of time remaining, since the first has less room to grow before expiration. That shrinking value is called time decay.
3. Either side can close the trade early
Most contracts don't run to expiration or exercise. More than 72% of contracts get closed out before expiration, according to the Options Industry Council. About 22% expire worthless, and only 6% get exercised.
A buyer can close by selling the contract back into the market, pocketing or losing the difference between the premium they paid and what they can now get. A seller can close by buying back the contract to cancel their obligation, ending the trade on their own terms instead of waiting to see what the stock does.
4. The call's buyer may exercise
Exercising means using the right the contract represents. A call buyer who exercises pays the strike price in cash and receives 100 shares. Standard stock options allow the buyer to exercise on any trading day up to expiration.
When the buyer exercises, the seller gets assigned. The OCC randomly picks a brokerage firm whose customer sold a matching contract, and that firm decides which of its customers gets assigned. The assigned seller must deliver 100 shares at the strike price, whether or not they already own them.
5. The call reaches expiration
If nobody closes or exercises the contract first, expiration settles it. A call finishing at or below its strike price expires worthless. On the $215 call, the buyer's loss stops at the $830 premium already paid, while the seller keeps the premium with no further obligation.
A call finishing at least a penny above its strike is generally exercised, a process the OCC calls exercise by exception, unless the buyer's brokerage submits instructions not to exercise it. Exercising this call takes $21,500 in cash to buy 100 shares at the $215 strike price. The seller who gets assigned hands over those shares in exchange for the cash.
What is a long call?
Buying a call, also called going long a call, is the more familiar side of the trade for anyone coming from stock investing. The buyer pays a premium up front for a shot at the stock's potential gains. If things don't work out, the buyer's maximum loss is limited to that payment.
How a long call works
A long call generally gains value as its underlying asset rises and loses value as the asset falls, all else equal. If the asset stays flat, time decay typically reduces the call's value as expiration approaches.
The call typically moves by fewer dollars than the underlying asset, but that smaller move plays out against a much smaller base, since the premium is only a fraction of what the shares themselves would cost. That's what gives a call its leverage. A modest move in the asset can translate into a much larger percentage move in the call's value.
That leverage works both ways, but the loss has a clear limit. No matter how far the asset falls, the call can't cost the buyer more than the premium they already paid for it. Exercising the call is a separate cost, though. It still requires enough cash to purchase 100 shares at the strike price.
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Profit and loss (P/L) for a long call
Take that $215 Nvidia call again, bought at $830 for one contract, when Nvidia's stock was at $212.26.
Because equity options are American-style, this call could be exercised as soon as Nvidia trades above $215, not only at expiration. That $830 premium buys leverage. Owning the same 100 shares outright would cost $21,226 at Nvidia's price that day, but the call tracks that same stock move for roughly 4% of that cost.
Above $215, the call carries value at expiration, and each dollar Nvidia gains offsets a dollar of the premium paid. The buyer still ends up down until that value covers the full $830, and above that point, nothing caps the gain.
On the other hand, if Nvidia finishes at or below $215, the call is worthless, and its buyer loses exactly $830, whether the stock drops a little or a lot.
Breakeven for a long call
Breakeven is the point between losing money and turning a profit. For this $215 Nvidia call, the breakeven sits at $223.30, the $215 strike plus the $8.30 premium.
Notice that the strike and the breakeven aren't at the same point. The strike is where the option starts carrying value at expiration, but this value may not fully cover the premium. Breakeven is where that value finally covers the entire premium.
What is a short call?
Selling a call, also called going short a call or writing a call, is the opposite side of a long call. The call's writer collects a premium up front in exchange for an obligation to deliver shares at the strike price.
How a short call works
A short call responds to the same forces as a long call. All else equal, its market price tends to rise as the underlying asset rises, fall as the asset falls, and decline as expiration nears. However, the writer holds the call as a liability rather than an asset, so a falling call price is their preferred outcome, and time decay works in their favor instead of against them.
Leverage applies here, too, but in reverse. The seller's best outcome is collecting the full premium, which happens if the asset finishes at or below the strike and the call expires worthless.
Above the strike, the asset can climb by any amount, so the potential cost of writing a call has no fixed ceiling. This is why brokers hold collateral against that potential cost, a requirement known as margin.
A seller who owns the shares meets that requirement with the shares themselves, which the broker locks in place until the call closes. A seller who doesn't own them has to keep cash or other assets in the account, and the broker can raise that amount if the stock climbs.
Covered and uncovered calls
Whether selling a call is a modest, income-generating trade or a high-risk contract comes down to whether the seller already owns the 100 shares behind the contract.
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Covered call: The seller owns 100 shares of the stock and sells a call against them. If assigned, the seller simply delivers shares already on hand.
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Uncovered call: The seller doesn't own the shares. If assigned, they still have to deliver 100 shares at the strike price, leaving them short until they buy the shares on the open market, typically at a higher price than the strike they just sold at.
Profit and loss (P/L) for a short call
Going back to the Nvidia call, assume the covered-call seller buys 100 Nvidia shares at $212.26 and sells one $215 call for $8.20 a share, while the uncovered seller sells that same call without owning any shares.
On the covered side, the seller's gain caps out at the strike because the shares must be handed over at $215 if the call is assigned, no matter how much further Nvidia climbs. The $10.94 maximum profit per share combines $2.74 of stock gain, from $212.26 up to the strike, with the $8.20 premium collected.
The premium cushions a decline, but it doesn't remove the risk of owning shares that keep falling. If Nvidia somehow falls all the way to $0, the loss would run to $204.06 a share, slightly less than the $212.26 a shareholder without a short call would lose.
On the uncovered side, the maximum profit is the $820 premium, and the seller keeps all of it if Nvidia finishes at or below $215, since the call then expires worthless.
Above $215, that profit starts shrinking, since the seller now owes the difference between the stock price and the strike. That difference eats into the $8.20-per-share premium, and once Nvidia climbs enough to use up the entire premium, at $223.20, the seller is losing money with no ceiling on how far that loss can grow.
Breakeven for a short call
Breakeven for a seller is the point where the premium collected exactly offsets what the seller owes on the call.
A covered seller loses when the stock falls, since they own the shares. In our example, their breakeven is at $204.06, the $212.26 purchase price minus the $8.20 premium collected. Below $204.06, the premium no longer covers the decline.
An uncovered seller loses when the stock rises, since they still have to deliver shares they don't own. Their breakeven is at $223.20, the $215 strike plus the $8.20 premium. Above $223.20, the premium no longer covers the seller's loss.
3 reasons investors use calls
The same call option serves different purposes depending on which side of the trade an investor takes, how much capital they want to risk, and whether they already own the underlying shares.
1. Buying calls ahead of an expected rally
Buying calls lets an investor target a price move with a known, capped cost. Say Nvidia's stock rose 10% by the time the $215 call expired. Here's how that move plays out for 100 shares of the stock against one call contract bought at an $8.30 premium per share.
Assuming the buyer holds the call until expiration, the contract turns the same 10% stock move into roughly 12 times the return. This is because a single $830 call can control 100 Nvidia shares without tying up the cash a full stock purchase would require.
However, if Nvidia stays flat or drops, the entire premium is lost, while a shareholder in the same stock still holds their shares and can wait for the stock to potentially recover.
2. Selling covered calls for income
Selling a call against stock you already own turns that holding into extra income. When the shares are bought and the call is sold at the same time, the trade is called a buy-write.
The shares cover the seller's obligation if the call gets assigned, so selling it doesn't increase the seller's maximum possible loss, though it does cap the potential gain.
Using our $215 Nvidia call, the seller collects an $820 premium up front. As long as Nvidia's stock stays below $215, that premium keeps them ahead of a shareholder by the full $820.
Above $215, the seller hands over the shares at that strike price when assigned, no matter how high Nvidia goes, capping the seller's gain right there. Here's how the covered call seller compares with a shareholder if Nvidia's stock rose 10% before the call expired.
Selling the call turns part of that rally into income. This means that covered calls are a good fit for shareholders willing to sell at a specific point, and a poor fit for anyone who would regret giving up the stock mid-rally.
3. Selling uncovered calls when you don't expect a rally
Selling a call without owning the shares provides that same premium as a covered call, but with none of the protection the shares would provide if things go wrong. That's why uncovered calls fit someone who expects the asset to stay flat or fall.
Unlike buying a call or setting up a covered call, selling an uncovered call doesn't require paying a premium or buying shares up front. The seller collects the $820 premium immediately, and the broker holds margin against the trade instead of requiring cash or shares at the start.
Here's how that plays out at different prices for Nvidia at expiration.
At any price at or below $215, the seller keeps the $820 premium. A larger drop in Nvidia doesn't increase the seller's profit.
Above $215, each dollar the stock climbs shrinks the seller's profit. That profit turns into a loss above the $223.20 breakeven, and the loss keeps growing from there with no ceiling.
3 risks to watch out for when trading calls
Each version of a call option carries a different risk. A buyer can lose the premium paid, a covered seller can lose on the shares they hold, and an uncovered seller can lose far more than the premium collected if the stock moves against them.
1. The risks buyers take
A call buyer's worst case is losing the entire premium, which happens whenever the stock fails to clear the strike price by expiration. That can occur even after a real move in the stock's favor, since the move still has to outrun the premium already paid.
A call buyer is far more likely to lose the entire investment than a shareholder is, even though the dollar amount at risk is smaller. Nvidia would have to fall to $0 for a shareholder to lose their entire investment. A call buyer can lose their entire investment if they keep the contract until expiration and it finishes at or below the $215 strike.
2. The risks covered-call sellers take
A covered call still carries the risk of owning shares that can fall, while the call caps any gain above the strike price. A sharp drop leaves the premium covering only a small part of the loss. A strong rally means giving up any gains above the strike.
The maximum loss is slightly smaller than the loss on the shares alone because the premium cushions part of the decline. In our example, the maximum loss is about $204.06 a share if Nvidia fell to $0.
3. The risk uncovered-call sellers take
An uncovered call carries the most risk of any call type. Because there's no ceiling on how high a stock can rise, there's no ceiling on how much an uncovered call writer can lose. That loss can also arrive well before expiration if the seller is assigned early.
A shareholder's loss is capped at 100% of their investment, since a stock price can't fall below $0. An uncovered call writer has no equivalent floor. That open-ended risk is exactly why brokers only allow accounts with a higher approval level to access uncovered calls.
Call options FAQs
What do "in the money" and "out of the money" mean?
A call is in the money when the stock is trading above the strike price, and out of the money when it's below. On this Nvidia call, anything above $215 is in the money, anything below is out of the money, and exactly $215 is at the money. The terms describe whether the option carries any value if exercised right now, not whether the trade has been profitable.
What happens if my call expires exactly at the strike price?
It expires worthless. A call only carries value at expiration if the stock finishes above the strike, even by a penny, so landing exactly on the strike leaves nothing worth exercising. This situation is uncommon, though stocks sometimes settle right at a heavily traded strike.
What happens if I can't afford to exercise a call that finishes above strike?
Exercising Nvidia's $215 call takes $21,500 in cash for the 100 shares. Without that buying power, your brokerage may step in, but exactly how depends on its expiration policy. It may sell the contract for you before the close on expiration day, submit a do-not-exercise request that lets the contract expire worthless, or exercise the call anyway and immediately sell the resulting shares.
Editorial disclaimer: Information on this page is for educational purposes and not investment advice or a recommendation to buy any specific asset or platform or adopt any particular investment strategy. Independently research products and strategies before making any investment decision.
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