Strike, expiration and premium: how contract terms interact
Strike and expiration jointly determine an option's premium and exposure. Compare them using one chain rather than a single rule of thumb.
By OptionsKing. Publisher and editorial methods.
By the end of this lesson, you should be able to:
- Explain how strike changes premium and exposure.
- Distinguish average premium per day from theta.
- Use annualization to compare terms without forecasting income.
Begin with an outcome you can accept: a sale or purchase price and a period of commitment. Then compare the premiums available for those terms. Moving farther from the stock often reduces exercise probability, but it also reduces the credit and does not eliminate a large adverse move.
Dial one: the strike
Chipotle (CMG) at $38.40, September 19, 45 days out. Walk the call side up.
| Strike | IV | Bid | Ask | Mid | Delta | Volume | Open interest |
|---|---|---|---|---|---|---|---|
| $36 call | 41.0% | $3.60 | $3.75 | $3.67 | 0.711 | 214 | 3,118 |
| $37 call | 39.6% | $2.93 | $3.05 | $2.98 | 0.646 | 331 | 2,004 |
| $38 call | 38.4% | $2.32 | $2.41 | $2.36 | 0.573 | 1,207 | 6,442 |
| $39 call | 37.4% | $1.80 | $1.87 | $1.83 | 0.495 | 688 | 3,975 |
| $40 call | 36.6% | $1.35 | $1.41 | $1.38 | 0.416 | 2,946 | 22,107 |
| $41 call | 35.9% | $1.00 | $1.05 | $1.02 | 0.339 | 402 | 2,687 |
| $42 call | 35.3% | $0.71 | $0.76 | $0.73 | 0.268 | 1,015 | 9,204 |
| $43 call | 34.8% | $0.49 | $0.53 | $0.51 | 0.205 | 77 | 1,388 |
| $44 call | 34.4% | $0.33 | $0.38 | $0.35 | 0.153 | 12 | 640 |
| $45 call | 34.1% | $0.21 | $0.26 | $0.23 | 0.111 | 843 | 5,412 |
From $40 to $44 the delta roughly falls by a factor of three, from 0.416 to 0.153. The premium falls by a factor of four, from $138 to $35. That is the general shape: premium decays faster than risk as you go further out.
Which is the argument against the very far strike. The $45 call bids $0.21. Twenty one dollars, for six and a half weeks of holding an obligation, on a name that can move 8 percent on a Thursday. There is a whole page on why that trade is worse than it looks, and the short version is that the money is too small to matter and the tail is not.
It is also the argument against the near strike. The $39 call pays $183, which is real money, and it is 0.495 delta: a coin flip on whether your shares get taken. Strike selection has its own page and the usable band for most sellers sits between those two, around 0.20 to 0.30.
Dial two: the expiry
Here is where the intuition breaks. Same stock, same day, three expiries: 17 days, 45 days, 73 days.
| Strike | 17 days | Per day | 45 days | Per day | 73 days | Per day |
|---|---|---|---|---|---|---|
| $38 | $1.51 | $8.90 | $2.36 | $5.24 | $2.98 | $4.08 |
| $40 | $0.62 | $3.64 | $1.38 | $3.07 | $1.96 | $2.69 |
| $42 | $0.19 | $1.11 | $0.73 | $1.63 | $1.22 | $1.67 |
| $43 | $0.09 | $0.55 | $0.51 | $1.14 | $0.94 | $1.29 |
Read the per-day columns and the rule everyone repeats falls apart. "Sell short-dated, time decay works faster" is true at the money, where the 17-day $38 call pays $8.90 a day against $4.08 for the 73-day. Go out to the $43 strike and it reverses completely: $0.55 a day at 17 days, $1.29 a day at 73.
The reason is that a far strike needs time to be worth anything at all. Seventeen days leaves less opportunity for CMG to travel from $38.40 to $43, so the model prices that contract at nine cents. The move remains possible. The theta page draws both curves and they genuinely bend in opposite directions.
So the honest version of the expiry rule: on this snapshot, shorter dates offer more premium per day near the money, while longer dates offer more at the distant strikes. Which is one more reason the 0.20 to 0.30 delta band and the 30-to-50-day window keep turning up together. They are where the two effects meet.
What you are giving up in each direction
The expiry table compares total premium divided by days, not the next day's theta. A contract paying more per day is not necessarily more profitable: the stock may move, closing may cost more, and repeated short trades create additional execution decisions. Keep those distinctions when comparing rows.
Both dials cost something and the costs are not symmetric.
Further out on strike costs you money now, keeps your shares longer, and does nothing for the disaster case. A stock that gaps 25 percent blows through the $43 call and the $45 call on the same morning.
Further out in time costs you flexibility. A 73-day contract holds the position across two earnings dates on many names, locks your strike at a level chosen 73 days ago, and hands you back less premium per day at any strike near the money. It also means fewer decisions a year, which for some people is the point.
Nearer in time costs you in fills. Selling weeklies means 52 round trips a year, and crossing the spread 52 times is a real annual fee that never appears on a per-trade calculation.
The number that ties them together
Compare the $42 call at 45 days, $73 of credit, against the $40 call at 17 days, $62 of credit. The second one pays less. It also ties up your shares for 28 fewer days, which means you can do it again.
Annualizing is how you compare them, and it is where people fool themselves. $62 on $3,840 of stock over 17 days annualizes to 34.7 percent. That number assumes you get the same trade 21 more times this year, at the same volatility, with no assignment ever. The annualizing page lists the four assumptions buried in it, and the honest use of the figure is comparing two contracts today, not forecasting a year.
The $43 call pays more per day at 73 days than at 17 days. Does that establish the better trade?
Show the explanation
No. It establishes only the quoted premium per day for this snapshot. The longer contract commits the position for more time and exposes it to additional events. Compare acceptable strike, calendar, costs and capital before choosing.
Common questions
Does a shorter expiry always decay faster?
No. Decay depends on moneyness and other inputs. This example compares premium per calendar day, which is not the same as theta. At fixed inputs, at-the-money and far-out-of-the-money options can have different decay curves.
How far out of the money should I sell?
Choose a strike from the payoff, acceptable sale or purchase price, size, liquidity, and events. Delta can help compare exposure, but there is no universally suitable band.
What is the best number of days to expiration?
There is no universal best DTE. Compare remaining premium, gamma, event exposure, execution costs, and how often you can manage the position.
Why does the premium fall so fast as the strike goes up?
Because it is pricing a probability that is falling faster than the distance is growing. From the $40 to the $44 call, delta drops by roughly two thirds and the premium drops by three quarters.
Sources
Rules and thresholds above were checked against these documents on August 4, 2026. Exchange and broker rules change. Confirm anything you are about to act on with your own broker.
Keep reading
Do the math on your own trade
Every price in this article is an illustrative worked example, not a quote. Read Options basics for the rest of the series, and the disclaimer before you act on any of it. Selling options carries real risk of loss, and the loss can be far larger than the premium you collected.