Jade Biosciences (JBIO) director Mark Eisner files initial Form 3

Rhea-AI Filing Summary

Jade Biosciences, Inc. director Mark Eisner filed an initial Form 3, which is a statement of beneficial ownership for company insiders. This filing lists him as a director but does not report any buy, sell, or derivative transactions, indicating it is purely an initial ownership disclosure at this time.

Key Figures

Buy transactions: 0 transactions Sell transactions: 0 transactions Exercise transactions: 0 derivative exercises +2 more

5 metrics

Buy transactions 0 transactions Form 3 transaction summary

Sell transactions 0 transactions Form 3 transaction summary

Exercise transactions 0 derivative exercises Form 3 transaction summary

Gift transactions 0 gifts Form 3 transaction summary

Tax withholding entries 0 entries Form 3 transaction summary

Key Terms

Form 3, beneficial ownership, director

3 terms

Form 3 regulatory

"filed an initial Form 3, which is a statement of beneficial ownership"

Form 3 is the initial public filing that officers, directors and large shareholders must submit to report their ownership of a company’s securities when they become insiders. It acts like an opening inventory sheet that gives investors a starting point to see who holds significant stakes and to spot later trades or potential conflicts of interest, helping assess insider confidence and transparency.

beneficial ownership regulatory

"initial Form 3, which is a statement of beneficial ownership for company insiders"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

director financial

"lists Mark Eisner as a director but does not report any buy, sell, or derivative transactions"

AI-generated analysis. How Rhea-AI works. Not financial advice.

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FAQ

What does the Jade Biosciences (JBIO) Form 3 for Mark Eisner show?

The Form 3 lists Mark Eisner as a director of Jade Biosciences. It serves as his initial statement of beneficial ownership and shows no reported buy, sell, or derivative transactions in JBIO at the time of filing.

Did Mark Eisner buy or sell any Jade Biosciences (JBIO) shares in this Form 3?

No. The insider data show zero buy and zero sell transactions. The Form 3 functions only as an initial beneficial ownership statement, without any reported trading activity in Jade Biosciences shares.

What insider role does Mark Eisner have at Jade Biosciences (JBIO)?

Mark Eisner is reported as a director of Jade Biosciences, Inc. Being a director makes him a company insider, requiring SEC ownership reporting on Forms 3, 4, and 5 for his equity-related positions and transactions.

Are there any derivative securities reported for Mark Eisner in JBIO?

No derivative securities are reported. The derivative summary shows zero derivative transactions and no remaining derivative positions, indicating this Form 3 contains no options or similar instruments for Mark Eisner.

Does the Jade Biosciences (JBIO) Form 3 indicate gifts or tax withholdings?

No. The transaction summary shows zero gifts and zero tax-withholding entries. The filing is limited to identifying Mark Eisner as a director, without any related share transfers disclosed.

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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:			3235-0104
Estimated average burden
hours per response:			0.5

1. Name and Address of Reporting Person^*

Eisner Mark

(Last) (First) (Middle)

C/O JADE BIOSCIENCES, INC.

221 CRESCENT ST., BLDG. 23, STE. 105

(Street)

WALTHAM MASSACHUSETTS 02453

(City) (State) (Zip)

UNITED STATES

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
06/25/2026

3. Issuer Name and Ticker or Trading Symbol
Jade Biosciences, Inc. [ JBIO ]

3a. Foreign Trading Symbol

5. If Amendment, Date of Original Filed (Month/Day/Year)

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

Remarks:

Exhibit 24 - Power of Attorney.

No securities are beneficially owned.

	/s/ Elizabeth Balta, as attorney-in-fact for Mark Eisner	06/26/2026
	** Signature of Reporting Person	Date
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 5 (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 3: SEC 1473 (03-26)