[Form 4] Inhibrx Biosciences, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Viking Global and affiliated entities reported multiple sales of Inhibrx Biosciences, Inc. (INBX) common stock executed on 10/07/2025 at a price of $32.25 per share. The largest single reported sale was 308,643 shares, plus additional sales of 25,042 and 16,315 shares, reducing reported holdings across the reporting group to 1,267,823, 102,864 and 67,018 shares respectively depending on the specific vehicle or account. The filing lists multiple related reporting persons and entities that may be deemed to beneficially own the shares through fund and GP relationships, and includes the standard disclaimer limiting beneficial ownership claims to pecuniary interest. The Form 4 is a joint filing signed by Scott M. Hendler on behalf of the reporting persons.

Positive

• Transparent disclosure of multiple sales and updated holdings by Viking and affiliates

Negative

• Material disposition of INBX shares on 10/07/2025: 308,643 shares sold at $32.25
• Aggregate reduction across reported accounts (combined sales of 349, ... total reported shares) which lowers reported stake in INBX

Insights

Activist/Portfolio Manager

TL;DR: Large block sales on a single day trimmed multiple Viking-owned INBX positions.

What happened: Multiple affiliated funds and GPs sold INBX shares on 10/07/2025 at $32.25, including a 308,643-share sale, with remaining reported holdings of 1,267,823, 102,864 and 67,018 across different vehicles. The sales are recorded as direct dispositions from the specified vehicles.

Dependencies and near-term implications: The filing documents ownership through layered fund and GP structures; the report does not state motivation, future trading plans, or whether sales were pre-arranged under a plan. Investors should note the transaction date 10/07/2025 as the material action date and that beneficial ownership is disclaimed except for pecuniary interest.

SEC Form 4

FORM 4

UNITED 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
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X

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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^*

VIKING GLOBAL INVESTORS LP

(Last) (First) (Middle)

600 WASHINGTON BLVD.

FLOOR 11

(Street)

STAMFORD CT 06901

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Inhibrx Biosciences, Inc. [ INBX ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
10/07/2025

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

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

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

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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	10/07/2025		S		308,643	D	$32.25	1,267,823	I	See Explanation of Responses(1)(2)(3)(6)
Common Stock	10/07/2025		S		16,315	D	$32.25	67,018	I	See Explanation of Responses(1)(2)(4)(6)
Common Stock	10/07/2025		S		25,042	D	$32.25	102,864	I	See Explanation of Responses(1)(2)(5)(6)

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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person^*

VIKING GLOBAL INVESTORS LP

(Last) (First) (Middle)

600 WASHINGTON BLVD.

FLOOR 11

(Street)

STAMFORD CT 06901

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Viking Global Opportunities Parent GP LLC

(Last) (First) (Middle)

600 WASHINGTON BLVD.

FLOOR 11

(Street)

STAMFORD CT 06901

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Viking Global Opportunities GP LLC

(Last) (First) (Middle)

600 WASHINGTON BLVD.

FLOOR 11

(Street)

STAMFORD CT 06901

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Viking Global Opportunities Portfolio GP LLC

(Last) (First) (Middle)

600 WASHINGTON BLVD.

FLOOR 11

(Street)

STAMFORD CT 06901

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Viking Global Opportunities Illiquid Investments Sub-Master LP

(Last) (First) (Middle)

600 WASHINGTON BLVD.

FLOOR 11

(Street)

STAMFORD CT 06901

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

HALVORSEN OLE ANDREAS

(Last) (First) (Middle)

600 WASHINGTON BLVD.

FLOOR 11

(Street)

STAMFORD CT 06901

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Ott David C.

(Last) (First) (Middle)

600 WASHINGTON BLVD.

FLOOR 11

(Street)

STAMFORD CT 06901

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Shabet Rose Sharon

(Last) (First) (Middle)

600 WASHINGTON BLVD.

FLOOR 11

(Street)

STAMFORD CT 06901

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

Explanation of Responses:

1. Andreas Halvorsen, David C. Ott and Rose S. Shabet are Executive Committee members of certain management entities, including Viking Global Partners LLC, the general partner of Viking Global Investors LP ("VGI"), and Viking Global Opportunities Parent GP LLC ("Opportunities Parent"), the sole member of Viking Global Opportunities GP LLC ("Opportunities GP"), the sole member of Viking Global Opportunities Portfolio GP LLC ("Opportunities Portfolio GP"), the general partner of Viking Global Opportunities Illiquid Investments Sub-Master LP ("Opportunities Fund"). Opportunities Parent is also the sole member of Viking Global Opportunities Drawdown GP LLC ("VGOD GP"), the sole member of Viking Global Opportunities Drawdown Portfolio GP LLC ("VGOD Portfolio GP"), the general partner of Viking Global Opportunities Drawdown (Aggregator) LP ("VGOD").

2. VGI provides managerial services to various investment funds and vehicles, including Opportunities Fund, VGOD, and KAVRA 104 LLC ("KAVRA 104"). VGI, Opportunities Parent, Opportunities GP, Opportunities Portfolio GP, Opportunities Fund, Mr. Halvorsen, Mr. Ott and Ms. Shabet are, collectively, the "Reporting Persons." Each of VGI, Mr. Halvorsen, Mr. Ott and Ms. Shabet may be deemed to beneficially own all of the securities reported on this form.

3. These shares of Common Stock are held directly by Opportunities Fund. Because of the relationship between Opportunities Portfolio GP, Opportunities GP, Opportunities Parent and Opportunities Fund, each of Opportunities Portfolio GP, Opportunities GP and Opportunities Parent may be deemed to beneficially own the securities held directly by Opportunities Fund.

4. These shares of Common Stock are held directly by KAVRA 104. The membership interests of KAVRA 104 are held by Viking Global Opportunities LP and Viking Global Opportunities Intermediate LP. Opportunities GP is the general partner of Viking Global Opportunities LP and Viking Global Opportunities Intermediate LP. Because of the relationship between Opportunities GP, Opportunities Parent and KAVRA 104, each of Opportunities GP and Opportunities Parent may be deemed to beneficially own the shares of Common Stock held directly by KAVRA 104.

5. These shares of Common Stock are held directly by VGOD. Because of the relationship between Opportunities Parent and VGOD, Opportunities Parent may be deemed to beneficially own the shares of Common Stock held directly by VGOD.

6. The Reporting Persons disclaim beneficial ownership of these securities except to the extent of their pecuniary interest therein, and the inclusion of these securities in this report shall not be deemed an admission of beneficial ownership of the reported securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or for any other purpose.

Remarks:

(7) The Reporting Persons are jointly filing this Form 4 pursuant to Rule 16a-3(j) under the Exchange Act. (8) Scott M. Hendler is signing on behalf of Mr. Halvorsen, Mr. Ott and Ms. Shabet, each individually and as an Executive Committee Member of VIKING GLOBAL PARTNERS LLC, on behalf of VIKING GLOBAL INVESTORS LP, and as an Executive Committee Member of VIKING GLOBAL OPPORTUNITIES PARENT GP LLC, on behalf of itself and VIKING GLOBAL OPPORTUNITIES GP LLC, VIKING GLOBAL OPPORTUNITIES PORTFOLIO GP LLC and VIKING GLOBAL OPPORTUNITIES ILLIQUID INVESTMENTS SUB-MASTER LP, pursuant to authorization and designation letters dated February 9, 2021, which were filed with the Securities and Exchange Commission on June 7, 2021.

	/s/ Scott M. Hendler signing on behalf of O. Andreas Halvorsen (7)(8)	10/09/2025
	/s/ Scott M. Hendler signing on behalf of David C. Ott (7)(8)	10/09/2025
	/s/ Scott M. Hendler signing on behalf of Rose S. Shabet (7)(8)	10/09/2025
	** 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 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.

FAQ

What transactions did Viking Global report for INBX on 10/07/2025?

The filing reports sales on 10/07/2025 at $32.25 of 308,643, 25,042, and 16,315 shares by affiliated funds and vehicles.

How many INBX shares does Viking Global and affiliates report holding after the transactions?

Post-transaction reported holdings include 1,267,823, 102,864, and 67,018 shares across the specified entities.

Who signed the Form 4 on behalf of the reporting persons?

Scott M. Hendler signed the Form 4 on behalf of O. Andreas Halvorsen, David C. Ott, and Rose S. Shabet on 10/09/2025.

Do the reporting persons claim direct beneficial ownership of all reported shares?

No. The reporting persons disclaim beneficial ownership except to the extent of their pecuniary interest; ownership is reported through fund and GP relationships.

Were the sales executed pursuant to a 10b5-1 plan according to the filing?

The form includes a checked box indicating a transaction pursuant to a written plan may apply, but the filing does not provide plan details or explicit confirmation of a 10b5-1 program for these specific sales.