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Castle Biosciences (CSTL) COO sells 8,587 shares, retains over 127K

Filing Impact
(Moderate)
Filing Sentiment
(Negative)
Form Type
4

Rhea-AI Filing Summary

CASTLE BIOSCIENCES INC Chief Operating Officer Kristen M. Oelschlager reported an open-market sale of 8,587 shares of common stock at a weighted-average price of $20.71 per share on June 16, 2026. The sale was executed as a planned transaction under a Rule 10b5-1 trading plan adopted on March 17, 2026.

Following this sale, she holds 30,460 shares of common stock directly and 97,251 shares indirectly through The Fritz Shorter Trust, where she and her spouse serve as trustees and beneficiaries.

Positive

  • None.

Negative

  • None.
Insider Oelschlager Kristen M
Role Chief Operating Officer
Sold 8,587 shs ($178K)
Type Security Shares Price Value
Sale Common Stock 8,587 $20.71 $178K
holding Common Stock -- -- --
Holdings After Transaction: Common Stock — 30,460 shares (Direct, null); Common Stock — 97,251 shares (Indirect, The Fritz Shorter Trust)
Footnotes (1)
  1. These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person, on March 17, 2026. This transaction was executed in multiple trades at prices ranging from $20.51 to $20.95, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. Held by the Fritz Shorter Trust of which the Reporting Person and her spouse are the trustees and beneficiaries.
Shares sold 8,587 shares Open-market sale of common stock on June 16, 2026
Sale price $20.71 per share Weighted-average sale price for the reported transaction
Direct holdings after sale 30,460 shares Common stock held directly following the June 16, 2026 sale
Indirect trust holdings 97,251 shares Common stock held indirectly via The Fritz Shorter Trust
Trading plan adoption date March 17, 2026 Date Rule 10b5-1 trading plan was adopted
Price range of trades $20.51–$20.95 Range of execution prices for the multiple sale trades
Rule 10b5-1 plan regulatory
"These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person, on March 17, 2026."
A Rule 10b5-1 plan is a prearranged, written schedule that lets corporate insiders buy or sell company stock at set times or amounts, even if they later learn material nonpublic information. Think of it like setting an automatic thermostat for trades: it creates a clear record that trades were planned in advance, reducing the risk of insider-trading accusations and helping investors trust that insider transactions are routine rather than based on secret information.
weighted-average sale price financial
"The price reported above reflects the weighted-average sale price."
open-market sale financial
"transaction_action": "open-market sale""
An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.
indirect ownership financial
"ownership_type": "indirect""
trustees and beneficiaries financial
"of which the Reporting Person and her spouse are the trustees and beneficiaries."
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Form 4 Insider Transactions: What Each Field Means →
SEC Form 4
FORM 4UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number:3235-0287
Estimated average burden
hours per response:0.5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
X
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
1. Name and Address of Reporting Person*
Oelschlager Kristen M
(Last)(First)(Middle)
C/O CASTLE BIOSCIENCES, INC.
1500 W. PARKWOOD AVE SUITE 400
(Street)
FRIENDSWOOD TEXAS 77546
(City)(State)(Zip)
UNITED STATES
(Country)		2. Issuer Name and Ticker or Trading Symbol
CASTLE BIOSCIENCES INC [ CSTL ] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director10% Owner
XOfficer (give title below)Other (specify below)
Chief Operating Officer
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
06/16/2026		6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year)2A. Deemed Execution Date, if any (Month/Day/Year)3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeVAmount(A) or (D)Price
Common Stock06/16/2026S(1)8,587D$20.71(2)30,460D
Common Stock97,251IThe Fritz Shorter Trust(3)
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year)3A. Deemed Execution Date, if any (Month/Day/Year)4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year)7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Explanation of Responses:
1. These transactions were made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person, on March 17, 2026.
2. This transaction was executed in multiple trades at prices ranging from $20.51 to $20.95, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.
3. Held by the Fritz Shorter Trust of which the Reporting Person and her spouse are the trustees and beneficiaries.
Remarks:
/s/ Frank Stokes, Attorney-in-fact06/18/2026
** Signature of Reporting PersonDate
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transaction did CSTL executive Kristen Oelschlager report?

Kristen M. Oelschlager, Chief Operating Officer of Castle Biosciences, reported selling 8,587 shares of common stock in an open-market transaction at a weighted-average price of $20.71 per share on June 16, 2026, while retaining substantial direct and indirect shareholdings.

How many CSTL shares does Kristen Oelschlager hold after the reported sale?

After the sale, Kristen M. Oelschlager holds 30,460 Castle Biosciences common shares directly and 97,251 shares indirectly through The Fritz Shorter Trust, where she and her spouse are trustees and beneficiaries, indicating a continued significant equity position in the company.

Was the CSTL insider sale by Kristen Oelschlager part of a trading plan?

Yes, the sale was executed under a pre-established Rule 10b5-1 trading plan adopted by Kristen M. Oelschlager on March 17, 2026. Such plans allow executives to schedule trades in advance, helping separate routine diversification from discretionary market-timing decisions.

At what price did CSTL COO Kristen Oelschlager sell her shares?

The reported transaction used a weighted-average sale price of $20.71 per Castle Biosciences share. The sale occurred in multiple trades between $20.51 and $20.95, with the weighted-average figure disclosed to summarize overall pricing across the executed trades.

What is The Fritz Shorter Trust’s role in CSTL share ownership?

The Fritz Shorter Trust holds 97,251 Castle Biosciences common shares indirectly for Kristen M. Oelschlager and her spouse. They serve as trustees and beneficiaries, meaning this trust-based structure is used to hold a substantial portion of her equity interest in the company.