Enzon Pharmaceuticals (ENZN) ties Series C exchange to Viskase merger

Rhea-AI Filing Summary

Enzon Pharmaceuticals has launched an issuer tender offer to exchange each share of its Series C Non-Convertible Redeemable Preferred Stock for common stock. The number of common shares per preferred share equals that share’s aggregate liquidation preference divided by $7.83, after a reverse stock split.

The offer is aimed at all holders of the 40,000 outstanding Series C preferred shares and is linked to Enzon’s planned merger with Viskase Companies, Inc.. Completion of the exchange offer depends on all merger conditions being satisfied, including effectiveness of Enzon’s Form S-4 registration statement and required stockholder written consent approving the merger.

As of January 30, 2026, Enzon had 74,214,603 common shares and 40,000 Series C preferred shares outstanding. Cash in lieu of fractional common shares will come from Enzon’s cash on hand, and the company explicitly makes no recommendation on whether preferred holders should tender.

Insights

M&A and capital structure analyst

Enzon links a preferred-for-common exchange to its merger with Viskase.

Enzon Pharmaceuticals is offering Series C preferred holders common stock based on each share’s liquidation preference divided by $7.83. This restructures part of its capital stack from preferred to common as it pursues a merger with Viskase Companies, Inc..

The exchange offer is expressly conditioned on all Merger Agreement conditions, including effective Form S-4 and requisite stockholder written consent for the merger and related transactions. The company will fund only cash paid for fractional shares from its own cash on hand.

The filing notes 74,214,603 common shares and 40,000 Series C preferred shares outstanding as of January 30, 2026. Actual impact on ownership and float will depend on how many preferred holders tender. The company states it makes no recommendation about participating in the exchange.

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

SCHEDULE TO
TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1)
OF THE SECURITIES EXCHANGE ACT OF 1934

ENZON PHARMACEUTICALS, INC.

(Name of Subject Company and Filing Persons (Issuer))

Series C Non-Convertible Redeemable Preferred Stock
(Title of Class of Securities)

293904702
(CUSIP Number of Class of Securities)

Richard L. Feinstein

Chief Executive Officer, Chief Financial Officer and Secretary
Enzon Pharmaceuticals, Inc.

20 Commerce Drive, Suite 135
Cranford, New Jersey 07016
(732) 980-4500
(Name, address, and telephone numbers of person authorized to receive notices and
communications on behalf of filing persons)

Copies of communications to:

Todd E. Mason
Corby J. Baumann
Benjamin M. Russell
Thompson Hine LLP
300 Madison Avenue, 27th Floor

New York, New York 10017

(212) 344-5680

¨ Check the box if the filing relates solely to preliminary communications before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

¨	third-party tender offer subject to Rule 14d-1.
x	issuer tender offer subject to Rule 13e-4.
¨	going-private transaction subject to Rule 13e-3.
¨	amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer: ¨

If applicable, check the appropriate box(es) below to designate the appropriate rule provision(s) relied upon:

¨	Rule 13e-4(i) (Cross-Border Issuer Tender Offer)
¨	Rule 14d-1(d) (Cross-Border Third-Party Tender Offer)

This Tender Offer Statement on Schedule TO (this “Schedule TO”) is filed by Enzon Pharmaceuticals, Inc., a Delaware corporation (the “Company,” “us” or “we”). This Schedule TO relates to an exchange offer (the “Offer”) by the Company to each holder of its Series C Non-Convertible Redeemable Preferred Stock, $0.01 par value per share (the “Series C Preferred Stock”) to exchange each share of Series C Preferred Stock validly tendered and not validly withdrawn for a number of shares of the Company’s common stock, $0.01 par value per share (the “Common Stock”) equal to (i) the aggregate liquidation preference of each share of Series C Preferred Stock, divided by (ii) $7.83, after giving effect to the Reverse Stock Split (as defined in the Prospectus/Consent Solicitation/Offer to Exchange, dated January 28, 2026, filed with the Securities and Exchange Commission (the “SEC”) on January 28, 2026 (the “Prospectus/Consent Solicitation/Offer to Exchange”)). The Offer is made upon and subject to the terms and conditions set forth in the Prospectus/Consent Solicitation/Offer to Exchange, a copy of which is attached hereto as Exhibit (a)(4), and in the related Letter of Transmittal, a copy of which is attached hereto as Exhibit (a)(1)(A).

On January 28, 2026, the Company filed with the SEC a Registration Statement on Form S-4 (the “Registration Statement”), relating to (i) the issuance of Common Stock in connection with the proposed merger (the “Merger”) of the Company and Viskase Companies, Inc. (“Viskase”), and (ii) the offer to exchange shares of Common Stock to holders of shares of Series C Preferred Stock validly tendered and not validly withdrawn in the Offer.

The Offer is conditioned upon the satisfaction or waiver of all of the conditions to the consummation of the Merger set forth in the Agreement and Plan of Merger, dated June 20, 2025 by and among the Company, EPSC Acquisition Corp. (“EPSC”) and Viskase (the “Original Merger Agreement”), as amended by the First Amendment to the Agreement and Plan of Merger, dated October 24, 2025, by and among the Company, EPSC and Viskase (the “First Amendment to the Merger Agreement,” and, as amended, the “Merger Agreement”), including, without limitation, the effectiveness of the Registration Statement and the receipt by the Company of the requisite written consent of its stockholders approving the Merger and the other transactions contemplated by the Merger Agreement. The Company intends to complete the Offer substantially concurrently with the consummation of the Merger. Copies of the Original Merger Agreement and the First Amendment to the Merger Agreement are attached as Exhibit (d)(1) and Exhibit (d)(2) to this Schedule TO, respectively, and are incorporated by reference into this Schedule TO.

The terms and conditions of the Offer are set forth in the Prospectus/Consent Solicitation/Offer to Exchange, which is a part of the Registration Statement, and the Letter of Transmittal. Pursuant to General Instruction F to Schedule TO, the information contained in the Prospectus/Consent Solicitation/Offer to Exchange and the Letter of Transmittal, including any prospectus supplement or other supplement thereto related to the Offer hereafter filed with the SEC by the Company, is hereby expressly incorporated into this Schedule TO by reference in response to Items 1 through 11 of this Schedule TO and is supplemented by the information specifically provided for in this Schedule TO.

Item 1. Summary Term Sheet.

The information set forth in the sections of the Prospectus/Consent Solicitation/Offer to Exchange entitled “Summary of the Material Terms of the Merger and the Consent Solicitation” and “Summary of the Material Terms of the Series C Exchange Offer” is incorporated herein by reference.

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Item 2. Subject Company Information.

(a)  Name and Address. The name of the subject company and the issuer is Enzon Pharmaceuticals, Inc. The Company’s principal executive offices are located at 20 Commerce Drive, Suite 135, Cranford, New Jersey 07016, and its telephone number is (732) 980-4500.

(b)  Securities. As of January 30, 2026, there were (i) 74,214,603 shares of Common Stock outstanding and (ii) 40,000 shares of Series C Preferred Stock outstanding.

(c)  Trading Market and Price. The subject securities are 40,000 shares of Series C Preferred Stock of the Company. There is no trading market for the Series C Preferred Stock. The information regarding the principal market where the Company’s Common Stock is quoted and certain high and low sales prices for the shares of Common Stock is set forth in the section of the Prospectus/Consent Solicitation/Offer to Exchange entitled “Market Price and Dividend Information” and is incorporated herein by reference.

Item 3. Identity and Background of Filing Person.

(a)  Name and Address. The information set forth above under Item 2(a) is incorporated herein by reference. The information set forth in the sections of the Prospectus/Consent Solicitation/Offer to Exchange entitled “Information About Enzon’s Business – Employees and Executive Officers,” “Security Ownership of Certain Beneficial Owners of Enzon,” and “Interests of Executive Officers and Directors in the Merger – Interests of Enzon’s Executive Officers and Directors in the Merger Proposal” is incorporated herein by reference.

Item 4. Terms of the Transaction.

(a)(1) Material Terms of the Tender Offer. The information set forth in the sections of the Prospectus/Consent Solicitation/Offer to Exchange entitled “Questions and Answers About the Series C Exchange Offer,” “Summary of the Material Terms of the Series C Exchange Offer,” “The Merger,” “Series C Exchange Offer” and “Material U.S. Federal Income Tax Consequences” is incorporated herein by reference.

(a)(2) Material Terms of the Merger. The information set forth in the sections of the Prospectus/Consent Solicitation/Offer to Exchange entitled “Questions and Answers About the Merger and Consent Solicitation,” “Summary of the Material Terms of the Merger and the Consent Solicitation,” “The Merger,” “The Merger Agreement” and “Material U.S. Federal Income Tax Consequences” is incorporated herein by reference.

(b)  Purchases. The information set forth in the section of the Prospectus/Consent Solicitation/Offer to Exchange entitled “Series C Exchange Offer” is incorporated herein by reference.

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Item 5. Past Contracts, Transactions, Negotiations and Agreements.

(e)  Agreements Involving the Subject Company’s Securities. The information set forth in the sections of the Prospectus/Consent Solicitation/Offer to Exchange entitled “The Merger,” “The Merger Agreement,” “Series C Exchange Offer” and “IEH Support Agreement” is incorporated herein by reference.

Item 6. Purposes of the Transaction and Plans or Proposals.

(a)  Purposes. The information set forth in the sections of the Prospectus/Consent Solicitation/Offer to Exchange entitled “Questions and Answers About the Merger and Consent Solicitation,” “Questions and Answers About the Series C Exchange Offer” and “Series C Exchange Offer—Reasons for the Series C Exchange Offer” is incorporated herein by reference.

(b)  Use of Securities Acquired. The information set forth in the sections of the Prospectus/Consent Solicitation/Offer to Exchange entitled “Questions and Answers About the Merger and Consent Solicitation,” “Questions and Answers About the Series C Exchange Offer,” “Series C Exchange Offer—Reasons for the Series C Exchange Offer” and “Series C Exchange Offer—Terms of the Series C Exchange Offer” is incorporated herein by reference.

(c)  Plans. The information set forth in the sections of the Prospectus/Consent Solicitation/Offer to Exchange entitled “Questions and Answers About the Merger and Consent Solicitation,” “Questions and Answers About the Series C Exchange Offer,” “Summary of the Material Terms of the Merger and the Consent Solicitation,” “The Merger,” and “Market Price and Dividend Information” is incorporated herein by reference.

Item 7. Source and Amount of Funds or Other Consideration.

(a)  Source of Funds. The information set forth in the section of the Prospectus/Consent Solicitation/Offer to Exchange entitled “Questions and Answers About the Series C Exchange Offer” and “Series C Exchange Offer” is incorporated herein by reference. The cash in lieu of any fractional shares of Common Stock will be paid from Enzon’s cash on hand.

(b)  Conditions. The information set forth in the section of the Prospectus/Consent Solicitation/Offer to Exchange entitled “The Series C Exchange Offer — Conditions of the Series C Exchange Offer” is incorporated herein by reference.

Item 8. Interest in Securities of the Subject Company.

(a)  Securities Ownership. The information set forth in the sections of the Prospectus/Consent Solicitation/Offer to Exchange entitled “Questions and Answers About the Series C Exchange Offer” and “Security Ownership of Certain Beneficial Owners of Enzon” is incorporated herein by reference.

(b)  Securities Transactions. Except as set forth in the Prospectus/Consent Solicitation/Offer to Exchange, neither the Company, nor any of its directors, executive officers or controlling persons, or any executive officers, directors, managers or partners of any of its controlling persons, has engaged in any transactions in the Series C Preferred Stock in the last 60 days.

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Item 9. Persons/Assets, Retained, Employed, Compensation or Used.

(a)  Solicitations or Recommendations. The information set forth in the section of the Prospectus/Consent Solicitation/Offer to Exchange entitled “Series C Exchange Offer” is incorporated herein by reference. None of the Company, its management, and its board of directors is making any recommendation as to whether holders of Series C Preferred Stock should tender Series C Preferred Stock for exchange in the Offer.

Item 10. Financial Statements.

(a)  Financial Information. The financial statements and other financial information of the Company included in the Prospectus/Consent Solicitation/Offer to Exchange in the section entitled “Index to Consolidated Financial Statements of Enzon Pharmaceuticals, Inc. and Subsidiaries” are incorporated by reference herein. The full text of such financial statements and other financial information, as well as the other documents the Company has filed with the SEC prior to, or will file with the SEC subsequent to, the filing of this Schedule TO relating to the Offer are available for inspection and copying from the SEC’s website at www.sec.gov.

(b)  Pro Forma Information. The pro forma financial statements and other financial information of the Company included in the Prospectus/Consent Solicitation/Offer to Exchange in the section entitled “Unaudited Pro Forma Condensed Combined Financial Information” are incorporated by reference herein.

Item 11. Additional Information.

(a)  Agreements, Regulatory Requirements and Legal Proceedings. The information set forth in the Prospectus/Consent Solicitation/Offer to Exchange and the Letter of Transmittal is incorporated herein by reference.

(c)  Other Material Information. The information set forth in the Prospectus/Consent Solicitation/Offer to Exchange and the Letter of Transmittal is incorporated herein by reference.

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Item 12. Exhibits.

(a) Exhibits.

				Incorporated by Reference
Exhibit No.		Description		Schedule/ Form		File Number		Exhibit		Filing Date
(a)(1)(A)		Letter of Transmittal		Form S-4/A		333-293019		99.9		January 30, 2026
(a)(1)(B)		Notice of Guaranteed Delivery		Form S-4/A		333-293019		99.10		January 30, 2026
(a)(1)(C)		Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees		Form S-4/A		333-293019		99.11		January 30, 2026
(a)(1)(D)		Letter to Clients for Use by Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees		Form S-4/A		333-293019		99.12		January 30, 2026
(a)(1)(E)		Press release issued by Enzon Pharmaceuticals, Inc., dated January 30, 2026		Form S-4/A		333-293019		99.13		January 30, 2026
(a)(4)		Prospectus/Consent Solicitation/Offer to Exchange		Form S-4/A		333-293019		—		January 28, 2026
(a)(5)		Press Release, dated October 24, 2025		Form 8-K		000-12957		99.1		October 24, 2025
(d)(1)		Agreement and Plan of Merger, dated as of June 20, 2025, by and between Enzon Pharmaceuticals, Inc., EPSC Acquisition Corp., and Viskase Companies, Inc.		Form S-4		333-293019		2.1		January 28, 2026
(d)(2)		First Amendment to Agreement and Plan of Merger, dated as of October 24, 2025, by and between Enzon Pharmaceuticals, Inc., EPSC Acquisition Corp., and Viskase Companies, Inc.		Form S-4		333-293019		2.2		January 28, 2026
(d)(3)		Support Agreement, dated as of June 20, 2025, by and between Icahn Enterprises Holdings L.P. and certain of its affiliates, Enzon Pharmaceuticals, Inc. and Viskase Companies, Inc.		Form S-4		333-293019		10.14		January 28, 2026
(d)(4)		First Amendment to Support Agreement, dated as of October 24, 2025, by and between Icahn Enterprises Holdings L.P. and certain of its affiliates, Enzon Pharmaceuticals, Inc. and Viskase Companies, Inc.		Form S-4		333-293019		10.24		January 28, 2026

(b) Filing Fee Exhibit.

Filing Fee Table.

Item 13. Information Required By Schedule 13E-3.

Not applicable.

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SIGNATURE

After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

	ENZON PHARMACEUTICALS, INC.
	By:	/s/ Richard L. Feinstein
	Name:	Richard L. Feinstein
	Title:	Chief Executive Officer, Chief Financial Officer and Secretary

Dated: January 30, 2026

FAQ

What is Enzon (ENZN) offering in the Series C preferred exchange?

Enzon is offering to exchange each Series C Non-Convertible Redeemable Preferred share for common stock. The number of common shares equals that share’s aggregate liquidation preference divided by $7.83, calculated after a reverse stock split, as described in the Prospectus/Consent Solicitation/Offer to Exchange.

How is the Series C exchange ratio of liquidation preference divided by $7.83 defined?

Each Series C preferred share can be exchanged for Enzon common stock based on that share’s total liquidation preference divided by $7.83. The company states this calculation is made after giving effect to a reverse stock split detailed in the Prospectus/Consent Solicitation/Offer to Exchange.

What conditions must be satisfied for Enzon’s Series C exchange offer to close?

The exchange offer is conditioned on all merger conditions in the Merger Agreement with Viskase being satisfied or waived. These include effectiveness of Enzon’s Form S-4 registration statement and receipt of the requisite stockholder written consent approving the merger and related transactions.

How is Enzon funding any cash payments in the Series C exchange offer?

Enzon states that any cash paid will be only for fractional common shares resulting from the exchange calculations. The company specifies that this cash in lieu of fractional shares will come from Enzon’s existing cash on hand, rather than from external financing arrangements.

How many Enzon shares are currently outstanding before the Series C exchange?

As of January 30, 2026, Enzon reports 74,214,603 common shares outstanding and 40,000 shares of Series C Preferred Stock outstanding. These figures provide a baseline capital structure before any impact from the preferred-for-common exchange or the proposed merger with Viskase.

Does Enzon recommend that Series C holders tender into the exchange offer?

Enzon explicitly states that neither the company, its management, nor its board of directors is making any recommendation. Holders of Series C Preferred Stock are not being advised by Enzon to tender or not tender their shares in the exchange offer.