How Option Greeks Change Over Time

The option greeks are not fixed numbers. They reprice every session as their inputs move: the stock, the calendar, and volatility. The clearest way to see it is to pin two real contracts and watch them age side by side. Here are a SPY call and put at the same $740 strike, both expiring June 18, 2026, traced from May 1 to the week before expiry. Same underlying, same strike, same expiry, opposite direction. Their greeks come out as near mirror images.

First, the stock the two options were tracking. SPY opened the window at $720, climbed to $759.63 by Jun 2, fell to $722.88 on Jun 10, then rallied back to $753.91 by Jun 15.

SELECT date,
       formatDateTime(date, '%b %e') AS date_label,
       round(avg(underlying_close), 2) AS spy_price
FROM global_markets.options_greeks
WHERE ticker = 'O:SPY260618C00740000' AND date BETWEEN '2026-05-01' AND '2026-06-15' AND implied_volatility > 0.02
GROUP BY date
ORDER BY date

Same strike, mirror-image prices

The call started cheap and the put started rich: on May 1 the call marked $7.22 while the put marked $23.05, with SPY sitting below the shared $740 strike. As the stock rose through the strike into early June, the two crossed: at SPY's Jun 2 peak the call reached $23.5 and the put fell to $2.79. When SPY dropped on Jun 5, the pair flipped again. By the last session the call was worth $15.41 and the put just $1.16.

SELECT c.date AS date,
       formatDateTime(c.date, '%b %e') AS date_label,
       round(avg(c.option_close), 2) AS call_price,
       round(avg(p.option_close), 2) AS put_price
FROM global_markets.options_greeks c
INNER JOIN global_markets.options_greeks p ON c.date = p.date
WHERE c.ticker = 'O:SPY260618C00740000' AND p.ticker = 'O:SPY260618P00740000'
  AND c.date BETWEEN '2026-05-01' AND '2026-06-15'
  AND c.implied_volatility > 0.02 AND p.implied_volatility > 0.02
GROUP BY c.date
ORDER BY date

Every number below is one of the five greeks reading off these two price paths. For the full definitions, start with the option greeks explained.

The call's greeks over its life

SELECT date,
       formatDateTime(date, '%b %e') AS date_label,
       round(avg(delta), 3) AS delta,
       round(avg(gamma), 4) AS gamma,
       round(avg(theta), 3) AS theta,
       round(avg(vega), 3) AS vega,
       round(avg(implied_volatility) * 100, 1) AS iv_pct
FROM global_markets.options_greeks
WHERE ticker = 'O:SPY260618C00740000' AND date BETWEEN '2026-05-01' AND '2026-06-15' AND implied_volatility > 0.02
GROUP BY date
ORDER BY date

Delta is how much the option moves per $1 in the stock, and roughly its odds of finishing in the money. The call opened at a delta of 0.327 with SPY under the strike, behaving like a third of a share. As SPY rose above $740 the delta climbed toward 1: it read 0.809 at the Jun 2 peak and 0.837 on the final session. Full mechanics in what option delta is.

Gamma is how fast delta itself changes, and it runs highest when the stock sits right on the strike. The call's gamma opened at 0.0105 and ran up to 0.0281 on Jun 12, with SPY hovering near $740 in mid-June. See option gamma.

Theta is the value the option sheds per day as expiry nears, and that bleed speeds up into the final week. The call's theta went from -0.153 on May 1 to -0.664 on Jun 15, a much steeper daily drain near June 18. More in option theta.

Vega is how much the option moves per one-point change in implied volatility. Vega shrinks as expiry approaches, yet it ticked up across the Jun 5 selloff: 0.434 at the peak, then 0.548 two sessions later, alongside the call's IV climbing from 13.2% at the start to 21.2% at the Jun 10 low. Read option vega for the full picture.

The put's greeks: the mirror

SELECT date,
       formatDateTime(date, '%b %e') AS date_label,
       round(avg(delta), 3) AS delta,
       round(avg(gamma), 4) AS gamma,
       round(avg(theta), 3) AS theta,
       round(avg(vega), 3) AS vega,
       round(avg(implied_volatility) * 100, 1) AS iv_pct
FROM global_markets.options_greeks
WHERE ticker = 'O:SPY260618P00740000' AND date BETWEEN '2026-05-01' AND '2026-06-15' AND implied_volatility > 0.02
GROUP BY date
ORDER BY date

Put the two panels next to each other and the symmetry is exact. A put's delta is negative: it gains as the stock falls. The put opened at a delta of -0.681 and ran toward -1 as SPY sank, hitting -0.796 at the Jun 10 trough. It then relaxed to -0.155 once SPY rallied back over the strike and the put drifted out of the money.

Gamma is the one greek the call and put share rather than mirror: both read the same curvature at the same strike. The put's gamma opened at 0.0109 and peaked at 0.023 on Jun 12, the same near-strike session that maxed the call's gamma. Theta bled the put too, steepening from -0.07 on May 1 to -0.552 at the end. And vega rose on the same selloff: 0.44 at the Jun 2 high, then 0.55 on Jun 5 as the put's IV jumped from 12.6% to 21.8% on Jun 11.

Why the greeks never sit still

Each greek is a slope, and a slope changes as you slide along the curve. Move the stock and delta changes (that motion is gamma). Turn the calendar page and theta grinds a little value off every day, faster as the expiration date closes in. Shift the fear priced into options and vega repositions the whole surface. The two contracts here started weeks apart in price and delta, crossed twice as SPY swung, and converged toward their expiry values from opposite ends. Nothing about any of the five numbers was constant for even a single session.

That is the practical lesson. A greek you read on Monday is a snapshot, not a setting. A position that is delta-neutral at the open can carry real directional risk by the close once gamma has done its work, and a vega bet placed in calm can swing hard when a selloff lifts implied volatility across the board.

FAQ

Do call and put greeks move in opposite directions?

Mostly. Delta is the clearest mirror: a call's delta runs from 0 toward +1 as the stock rises, while a put's delta runs from 0 toward -1 as the stock falls. Theta and vega point the same way for both (both lose time value, both gain when volatility rises), and gamma is actually shared: a call and a put on the same strike and expiry carry the same gamma.

Why does an option's delta change every day?

Delta is the odds-weighted sensitivity to the stock, and those odds move as the stock does. That rate of change is gamma. In this trace the call's delta climbed from 0.327 to 0.837 as SPY worked above the $740 strike, without anyone re-quoting it: the delta repriced itself every session the stock moved.

Which greek changes fastest near expiration?

Theta and gamma both intensify into the final week. Theta's daily bleed steepens as fewer days remain to spread the decay over, and gamma spikes when the stock sits near the strike close to expiry. In this contract the call's theta went from -0.153 to -0.664 across its life.

What makes vega rise even as an option ages?

Vega falls with time all else equal, yet all else is rarely equal. When implied volatility jumps, vega on the surviving days can tick back up. Both contracts here saw vega rise across the early-June selloff even as expiry drew nearer, tracking the spike in their implied volatility.

You can pull this exact trace, or swap in any ticker and strike, on the Strasmore terminal and watch the greeks move for yourself.