CSTL · Castle Biosciences Inc · Options Chain

Track CSTL — free

$32.70 -0.06 (-0.18%)

Russell 2000 member Rebalance outlook locked

Market Cap

$1.00B

30.55M

Options Chain

Underlying $32.70 · today Options Calculator

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Positioning

Sep 18, 2026 · 9 days to expiry · 18 contracts · mixed daily-bar sessions · Jul 31, 2026–Sep 4, 2026; 10 unknown

Put / call OI

0.20

Call-heavy positioning

Open interest

as of Sep 4, 2026

Volume

—

dated and unknown daily-bar sessions

Max pain

$25.00

$7.70 below spot

ATM implied vol

72.1%

market's expected move

Open interest by strike

Calls Puts

12.5

17.5

22.5

Chain

Click any strike for greeks, breakeven and the calculator

Expiry

Sep 18 9d Oct 16 37d Jan 15 128d Apr 16 219d

Calls								Puts
OI	Vol	IV	Δ	Bid	Ask	Last	Strike	Last	Bid	Ask	Δ	IV	Vol	OI
—	—	—	—	$18.90	$21.30	—		—	$0.00	$0.75	—	—	—	—
Call · $12.5 In the money Daily-bar session Unknown Quote as of 2026-09-09 15:53:29.421 UTC Last — Breakeven — Implied vol — Delta — Gamma — Theta — Vega — Open interest — OI effective date — Model this call Put · $12.5 Daily-bar session Unknown Quote as of 2026-09-09 16:07:34.240 UTC Last — Breakeven — Implied vol — Delta — Gamma — Theta — Vega — Open interest — OI effective date — Model this put
—	—	—	—	$16.50	$18.80	—		—	$0.00	$0.75	—	—	—	—
Call · $15 In the money Daily-bar session Unknown Quote as of 2026-09-09 15:59:57.588 UTC Last — Breakeven — Implied vol — Delta — Gamma — Theta — Vega — Open interest — OI effective date — Model this call Put · $15 Daily-bar session Unknown Quote as of 2026-09-09 16:05:21.729 UTC Last — Breakeven — Implied vol — Delta — Gamma — Theta — Vega — Open interest — OI effective date — Model this put
—	—	—	—	$14.00	$16.10	—		—	$0.00	$0.75	—	—	—	—
Call · $17.5 In the money Daily-bar session Unknown Quote as of 2026-09-09 15:53:29.421 UTC Last — Breakeven — Implied vol — Delta — Gamma — Theta — Vega — Open interest — OI effective date — Model this call Put · $17.5 Daily-bar session Unknown Quote as of 2026-09-09 16:05:21.729 UTC Last — Breakeven — Implied vol — Delta — Gamma — Theta — Vega — Open interest — OI effective date — Model this put
2	2	—	—	$11.50	$13.60	$8.61		—	$0.00	$0.75	—	—	—	—
Call · $20 In the money Daily-bar session Jul 31, 2026 Quote as of 2026-09-09 16:09:22.294 UTC Last $8.61 Breakeven $28.61 Implied vol — Delta — Gamma — Theta — Vega — Open interest 2 OI effective date Sep 4, 2026 Model this call Put · $20 Daily-bar session Unknown Quote as of 2026-09-09 16:07:34.240 UTC Last — Breakeven — Implied vol — Delta — Gamma — Theta — Vega — Open interest — OI effective date — Model this put
1	1	—	—	$8.30	$10.90	$10.90		—	$0.00	$0.75	—	—	—	—
Call · $22.5 In the money Daily-bar session Aug 20, 2026 Quote as of 2026-09-09 16:08:15.992 UTC Last $10.90 Breakeven $33.40 Implied vol — Delta — Gamma — Theta — Vega — Open interest 1 OI effective date Sep 4, 2026 Model this call Put · $22.5 Daily-bar session Unknown Quote as of 2026-09-09 16:07:34.240 UTC Last — Breakeven — Implied vol — Delta — Gamma — Theta — Vega — Open interest — OI effective date — Model this put
1	1	—	—	$5.80	$8.40	$6.50		$0.47	$0.00	$0.75	—	—	4	4
Call · $25 In the money Daily-bar session Aug 4, 2026 Quote as of 2026-09-09 15:59:57.588 UTC Last $6.50 Breakeven $31.50 Implied vol — Delta — Gamma — Theta — Vega — Open interest 1 OI effective date Sep 4, 2026 Model this call Put · $25 Daily-bar session Aug 5, 2026 Quote as of 2026-09-09 16:05:21.727 UTC Last $0.47 Breakeven $24.53 Implied vol — Delta — Gamma — Theta — Vega — Open interest 4 OI effective date Sep 4, 2026 Model this put
4	1	35.5%	0.946	$1.50	$4.10	$3.37		$2.25	$0.00	$2.55	—	—	2	1
Call · $30 In the money Daily-bar session Sep 4, 2026 Quote as of 2026-09-09 15:59:57.588 UTC Last $3.37 Breakeven $33.37 Implied vol 35.5% Delta 0.946 ≈95% ITM Gamma 0.06 Theta -0.014 Vega 0.006 Open interest 4 OI effective date Sep 4, 2026 Model this call Put · $30 Daily-bar session Aug 18, 2026 Quote as of 2026-09-09 16:08:03.483 UTC Last $2.25 Breakeven $27.75 Implied vol — Delta — Gamma — Theta — Vega — Open interest 1 OI effective date Sep 4, 2026 Model this put
Underlying $32.70
16	11	—	—	$0.00	$1.30	$1.10		—	$1.90	$3.90	-0.701	72.1%	—	—
Call · $35 Daily-bar session Sep 2, 2026 Quote as of 2026-09-09 16:15:53.172 UTC Last $1.10 Breakeven $36.10 Implied vol — Delta — Gamma — Theta — Vega — Open interest 16 OI effective date Sep 4, 2026 Model this call Put · $35 In the money Daily-bar session Unknown Quote as of 2026-09-09 16:36:34.964 UTC Last — Breakeven — Implied vol 72.1% Delta -0.701 ≈70% ITM Gamma 0.094 Theta -0.069 Vega 0.018 Open interest — OI effective date — Model this put
1	1	—	—	$0.00	$2.15	$0.25		—	$6.60	$9.20	-0.805	131.9%	—	—
Call · $40 Daily-bar session Aug 21, 2026 Quote as of 2026-09-09 16:07:34.489 UTC Last $0.25 Breakeven $40.25 Implied vol — Delta — Gamma — Theta — Vega — Open interest 1 OI effective date Sep 4, 2026 Model this call Put · $40 In the money Daily-bar session Unknown Quote as of 2026-09-09 15:25:22.404 UTC Last — Breakeven — Implied vol 131.9% Delta -0.805 ≈81% ITM Gamma 0.041 Theta -0.1 Vega 0.014 Open interest — OI effective date — Model this put

About this data

Each contract's last price, day range and volume belong to the daily-bar session shown in its details; unknown means the source omitted that timestamp. Open interest has its own effective date shown separately; implied volatility and greeks are model values computed when fetched. This chain has mixed daily-bar sessions · Jul 31, 2026–Sep 4, 2026; 10 unknown. Positioning totals are shown only when every returned open-interest value has the same known effective date. Bid and ask are real-time consolidated OPRA readings.

In-the-money strikes are tinted, deepening toward the money, and the bar beside each open-interest figure scales to the heaviest strike shown. Max pain is the listed strike where the most open interest would expire worthless — a positioning reference, not a forecast.

Key facts CIK 1447362 CUSIP 14843C105 13F (30d) 117 filings 117 filers Visit website Investor relations