CSTL · Castle Biosciences Inc

Track CSTL — free Ask ALVIS about CSTL

$24.70 -0.79 (-3.08%) At close · Jul 24

Market Cap

$748.69M

30.33M

Options Chain

15-min delayed Underlying $24.70 · today Options Calculator

Positioning

Aug 21, 2026 · 27 days to expiry · 14 contracts

Put / call OI

0.45

Call-heavy positioning

Open interest

contracts outstanding

Volume

traded today

Max pain

$22.50

$2.20 below spot

ATM implied vol

86.8%

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

Aug 21 27d Sep 18 55d Oct 16 83d Jan 15 174d

Calls						Puts
OI	Vol	IV	Δ	Last	Strike	Last	Δ	IV	Vol	OI
0	—	201.2%	0.936	—		—	—	—	—	0
Call · $12.5 In the money Last — Breakeven — Implied vol 201.2% Delta 0.936 ≈94% ITM Gamma 0.009 Theta -0.032 Vega 0.008 Open interest 0 Model this call Put · $12.5 Last — Breakeven — Implied vol — Delta — Gamma — Theta — Vega — Open interest 0 Model this put
0	—	145.6%	0.928	—		—	-0.077	151.2%	—	0
Call · $15 In the money Last — Breakeven — Implied vol 145.6% Delta 0.928 ≈93% ITM Gamma 0.014 Theta -0.026 Vega 0.009 Open interest 0 Model this call Put · $15 Last — Breakeven — Implied vol 151.2% Delta -0.077 ≈8% ITM Gamma 0.014 Theta -0.027 Vega 0.009 Open interest 0 Model this put
0	—	132%	0.874	—		—	-0.094	110.3%	—	0
Call · $17.5 In the money Last — Breakeven — Implied vol 132% Delta 0.874 ≈87% ITM Gamma 0.023 Theta -0.036 Vega 0.015 Open interest 0 Model this call Put · $17.5 Last — Breakeven — Implied vol 110.3% Delta -0.094 ≈9% ITM Gamma 0.023 Theta -0.023 Vega 0.01 Open interest 0 Model this put
0	—	104.6%	0.816	—		$1.80	-0.138	80%	1	1
Call · $20 In the money Last — Breakeven — Implied vol 104.6% Delta 0.816 ≈82% ITM Gamma 0.039 Theta -0.037 Vega 0.016 Open interest 0 Model this call Put · $20 Last $1.80 Breakeven $18.20 Implied vol 80% Delta -0.138 ≈14% ITM Gamma 0.041 Theta -0.022 Vega 0.016 Open interest 1 Model this put
2	2	92.2%	0.695	$3.25		$1.90	-0.303	89.6%	1	4
Call · $22.5 In the money Last $3.25 Breakeven $25.75 Implied vol 92.2% Delta 0.695 ≈69% ITM Gamma 0.058 Theta -0.042 Vega 0.022 Open interest 2 Model this call Put · $22.5 Last $1.90 Breakeven $20.60 Implied vol 89.6% Delta -0.303 ≈30% ITM Gamma 0.059 Theta -0.039 Vega 0.022 Open interest 4 Model this put
Underlying $24.70
2	1	92.9%	0.535	$2.10		—	-0.476	80.6%	—	0
Call · $25 Last $2.10 Breakeven $27.10 Implied vol 92.9% Delta 0.535 ≈53% ITM Gamma 0.065 Theta -0.048 Vega 0.027 Open interest 2 Model this call Put · $25 In the money Last — Breakeven — Implied vol 80.6% Delta -0.476 ≈48% ITM Gamma 0.075 Theta -0.039 Vega 0.027 Open interest 0 Model this put
7	5	87.9%	0.246	$0.05		—	-0.897	54.6%	—	0
Call · $30 Last $0.05 Breakeven $30.05 Implied vol 87.9% Delta 0.246 ≈25% ITM Gamma 0.054 Theta -0.035 Vega 0.02 Open interest 7 Model this call Put · $30 In the money Last — Breakeven — Implied vol 54.6% Delta -0.897 ≈90% ITM Gamma 0.053 Theta -0.011 Vega 0.013 Open interest 0 Model this put

About this data

Greeks, implied volatility, open interest and the last price come from the latest daily snapshot and are 15-minute delayed. Bid and ask are not included on this plan.

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) 23 filings 23 filers Visit website Investor relations