Perspective Therapeutics holder sells 78K shares

A 10% owner-linked entity sold 78,145 CATX shares on August 31, 2026, and now reports holding about 11.6 million shares after a prior reverse split adjustment.

Rhea-AI Filing Summary

Perspective Therapeutics, Inc. (CATX) had a significant shareholder, Lantheus Holdings, Inc., report that its wholly owned subsidiary Lantheus Alpha Therapy, LLC sold 78,145 shares of CATX common stock on August 31, 2026, at a weighted average price of $3.143 per share. After this open-market sale, the entity reported holding 11,599,194 CATX shares, adjusted to reflect a prior 1-for-10 reverse stock split effective June 14, 2024. No Rule 10b5-1 trading plan is reported for this transaction.

Insider Trade Summary

Net Seller: 78,145 shares

Net Sell 1 txn

Insider Lantheus Holdings, Inc.

Role 10% Owner

Sold 78,145 shs ($246K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2, F3	78,145	$3.143	$246K

Holdings After Transaction: Common Stock — 11,599,194 shares (Direct)

Footnotes (3)

1. F1. Effective June 14, 2024, Perspective Therapeutics, Inc. ("CATX") effected a 1-for-10 reverse stock split of its common stock (the "Reverse Stock Split"). The amount of securities reported on this Form 4 has been adjusted to reflect the Reverse Stock Split.
2. F2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.095 to $3.165, inclusive. The reporting person undertakes to provide to CATX, any security holder of CATX or the staff of the Securities and Exchange Commission ("SEC"), upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2) to this Form 4.
3. F3. Represents securities directly held by Lantheus Alpha Therapy, LLC ("Lantheus"), a wholly owned direct subsidiary of Lantheus Holdings, Inc. ("Lantheus Holdings"). Under SEC rules and regulations, Lantheus Holdings may be deemed to have indirect beneficial ownership of the shares held by Lantheus, which has direct beneficial ownership.

Key Figures

Shares sold: 78,145 shares Weighted average sale price: $3.143 per share Sale price range: $3.095–$3.165 per share +3 more

6 metrics

Shares sold 78,145 shares Common stock sale by Lantheus Alpha Therapy, LLC on August 31, 2026

Weighted average sale price $3.143 per share Average price for 78,145 CATX shares sold on August 31, 2026

Sale price range $3.095–$3.165 per share Price range of multiple sale transactions included in the reported average

Shares held after transaction 11,599,194 shares CATX common stock reported owned after the August 31, 2026 sale

Reverse stock split ratio 1-for-10 CATX reverse stock split of common stock effective June 14, 2024

Reverse stock split effective date June 14, 2024 Date CATX implemented the 1-for-10 reverse stock split referenced in the Form 4

Key Terms

1-for-10 reverse stock split, weighted average price, indirect beneficial ownership

3 terms

1-for-10 reverse stock split financial

"effected a 1-for-10 reverse stock split of its common stock"

weighted average price financial

"The price reported in Column 4 is a weighted average price"

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

indirect beneficial ownership financial

"Lantheus Holdings may be deemed to have indirect beneficial ownership"

FAQ

What insider transaction did CATX disclose in this Form 4?

The filing reports that Lantheus Alpha Therapy, LLC, a subsidiary of Lantheus Holdings, Inc., sold 78,145 shares of Perspective Therapeutics, Inc. (CATX) common stock on August 31, 2026 in an open-market or private transaction.

At what price were the 78,145 CATX shares sold by the Lantheus-affiliated entity?

The sale was executed at a weighted average price of $3.143 per share. The shares were sold in multiple transactions at prices ranging from $3.095 to $3.165 per share, inclusive.

How many CATX shares does the reporting entity hold after this transaction?

After the August 31, 2026 sale, the Lantheus-affiliated entity reported holding 11,599,194 shares of CATX common stock. This share amount is adjusted to reflect CATX’s previously effected 1-for-10 reverse stock split.

Who is the reporting person in the CATX Form 4 and how are the shares held?

The reporting person is Lantheus Holdings, Inc., a more than 10% owner. The shares are directly held by Lantheus Alpha Therapy, LLC, its wholly owned subsidiary. Lantheus Holdings may be deemed to have indirect beneficial ownership of those shares.

Was the CATX insider sale made under a Rule 10b5-1 trading plan?

No. The Form 4 indicates no Rule 10b5-1 plan; the document-level checkbox for transactions under such a plan is not marked, and no footnote states that the trades were made pursuant to a trading plan.

How did CATX’s prior reverse stock split affect the Form 4 share figures?

CATX effected a 1-for-10 reverse stock split of its common stock effective June 14, 2024. The Form 4 states that the number of securities reported has been adjusted to reflect this reverse stock split.

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Available on EDGAR 09/02/2026 - 04:36 PM Accepted by SEC EDGAR 09/02/2026 - 04:36 PM Learn about SEC filing dates

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
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).

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^*

Lantheus Holdings, Inc.

(Last) (First) (Middle)

201 BURLINGTON ROAD, SOUTH BUILDING

(Street)

BEDFORD MASSACHUSETTS 01730

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Perspective Therapeutics, Inc. [ CATX ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/31/2026

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

X	Form 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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	08/31/2026		S		78,145(1)	D	$3.143(2)	11,599,194(1)	D(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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Effective June 14, 2024, Perspective Therapeutics, Inc. ("CATX") effected a 1-for-10 reverse stock split of its common stock (the "Reverse Stock Split"). The amount of securities reported on this Form 4 has been adjusted to reflect the Reverse Stock Split.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.095 to $3.165, inclusive. The reporting person undertakes to provide to CATX, any security holder of CATX or the staff of the Securities and Exchange Commission ("SEC"), upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (2) to this Form 4.

3. Represents securities directly held by Lantheus Alpha Therapy, LLC ("Lantheus"), a wholly owned direct subsidiary of Lantheus Holdings, Inc. ("Lantheus Holdings"). Under SEC rules and regulations, Lantheus Holdings may be deemed to have indirect beneficial ownership of the shares held by Lantheus, which has direct beneficial ownership.

	/s/ Eric M. Green, Vice President, Deputy General Counsel and Assistant Corporate Secretary	09/02/2026
	** 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 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)