Icahn entities lift Viskase (ENZN) stake to 93.7% after merger

Rhea-AI Filing Summary

Carl C. Icahn and affiliated entities report owning 13,426,451 shares of Viskase Holdings, Inc. common stock, representing 93.7% of the company’s 14,331,713 outstanding shares as of March 26, 2026. This amended Schedule 13D reflects changes tied to Viskase’s merger with Viskase Companies, Inc.

On March 25, 2026, the Icahn group exchanged 39,277 shares of preferred stock for 5,658,396 Viskase common shares under an IEH Support Agreement. On March 26, 2026, they received a further 7,407,489 Viskase shares in exchange for 150,810,078 Viskase Companies, Inc. shares at the merger closing. Three Icahn-affiliated executives—Robert Flint, Colin Kwak, and Dustin DeMaria—joined Viskase’s board of directors in connection with the merger.

Insights

Equity ownership and governance analyst

Icahn group reports 93.7% control stake in Viskase after merger.

Carl C. Icahn and related entities now beneficially own 13,426,451 Viskase shares, or 93.7% of the 14,331,713 shares outstanding as of March 26, 2026. This reflects the completed merger between Viskase Holdings, Inc. and Viskase Companies, Inc..

The position increased through two stock-for-stock steps: exchanging 39,277 preferred shares for 5,658,396 common shares under an IEH Support Agreement, and receiving 7,407,489 Viskase shares for 150,810,078 Viskase Companies, Inc. shares under the merger agreement. These are non-cash equity exchanges.

Board influence also rises, as three Icahn-affiliated individuals—Robert Flint, Colin Kwak, and Dustin DeMaria—were appointed to Viskase’s board at closing. Future company filings may detail any post-merger strategic or capital structure changes stemming from this concentrated ownership and board representation.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 19)

VISKASE HOLDINGS, INC.

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

293904108

(CUSIP Number)

Jesse Lynn, Esq.
Icahn Capital LP, 16690 Collins Avenue, Suite PH-1
Sunny Isles Beach, FL, 33160
305-442-4000

Joshua Apfelroth
Proskauer Rose LLP, Eleven Times Square
New York, NY, 10036
212-969-3000

Louis Rambo
Proskauer Rose LLP, 1001 Pennsylvania Ave. NW, Suite 600
Washington, DC, 20004
202-416-6800

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

03/25/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

schemaVersion:

SCHEDULE 13D

CUSIP Number(s): 293904108

1

Name of reporting person

CARL C ICAHN

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 13,426,451.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 13,426,451.00

11

Aggregate amount beneficially owned by each reporting person

13,426,451.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

93.7 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

CUSIP Number(s): 293904108

1

Name of reporting person

ICAHN ENTERPRISES HOLDINGS L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 13,426,451.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 13,426,451.00

11

Aggregate amount beneficially owned by each reporting person

13,426,451.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

93.7 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP Number(s): 293904108

1

Name of reporting person

ICAHN ENTERPRISES G.P. INC.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 13,426,451.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 13,426,451.00

11

Aggregate amount beneficially owned by each reporting person

13,426,451.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

93.7 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, par value $0.01 per share
(b)	Name of Issuer: VISKASE HOLDINGS, INC.
(c)	Address of Issuer's Principal Executive Offices: 333 East Butterfield Road, Suite 400, Lombard, ILLINOIS , 60148.
Item 1 Comment: This statement constitutes Amendment No. 19 to the Schedule 13D relating to the shares of Common Stock, par value $0.01 per share (the "Shares"), issued by Viskase Holdings, Inc. (formerly known as Enzon Pharmaceuticals, Inc.), a Delaware corporation (the "Issuer"), and amends the Schedule 13D relating to the Shares filed on March 14, 2008 (as previously amended, the "Original 13D"), on behalf of the Reporting Persons (as defined in Item 2 of Amendment No. 16 to the Schedule 13D). Capitalized terms used herein and not otherwise defined have the respective meanings ascribed thereto in the Original 13D.
Item 4.	Purpose of Transaction
	Item 4 of the Original 13D is hereby amended and supplemented as follows: On March 25, 2026, in connection with the closing of the previously announced Merger between the Issuer and Viskase Companies, Inc. ("Viskase") and pursuant to the terms of the IEH Support Agreement, the Reporting Persons exchanged 39,277 shares of Preferred Stock for 5,658,396 shares of the Issuer's Common Stock. On March 26, 2026 (the "Closing Date"), the Issuer completed the Merger with Viskase pursuant to the Merger Agreement. In connection with the Merger and pursuant to the Merger Agreement, the Reporting Persons received 7,407,489 shares of the Issuer in exchange for 150,810,078 shares of Viskase. Robert Flint, Colin Kwak, and Dustin DeMaria were appointed to the Issuer's board of directors in connection with the closing of the Merger. Mr. Flint is the Chief Accounting Officer of Icahn Enterprises L.P. Mr. Kwak is the head trader at Icahn Capital LP, an affiliate of the Reporting Persons. Mr. DeMaria is a Senior Analyst at Ichan Enterprises L.P., an affiliate of the Reporting Persons.
Item 5.	Interest in Securities of the Issuer
(a)	Items (a)-(c) of the Original 13D are hereby amended and supplemented as follows: The information set forth in rows 11 and 13 of the cover pages hereto is incorporated herein by reference. The percentages set forth on the cover pages are based on 14,331,713 outstanding Shares as of March 26, 2026, as reported by the Issuer to the Reporting Persons.
(b)	The information set forth in rows 7-10 of the cover pages hereto is incorporated herein by reference.
(c)	The information set forth in Item 4 herein is incorporated herein by reference. Except for the transaction set forth in Item 4, none of the Reporting Persons effected any transaction in the Shares in the past 60 days.

SIGNATURE

After reasonable 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.

CARL C ICAHN

Signature:	/s/ Carl C. Icahn
Name/Title:	Carl C. Icahn
Date:	03/27/2026

ICAHN ENTERPRISES HOLDINGS L.P.

Signature:	/s/ Ted Papapostolou
Name/Title:	Ted Papapostolou, Chief Financial Officer
Date:	03/27/2026

ICAHN ENTERPRISES G.P. INC.

Signature:	/s/ Ted Papapostolou
Name/Title:	Ted Papapostolou, Chief Financial Officer
Date:	03/27/2026

FAQ

What ownership stake in Viskase Holdings, Inc. does Carl Icahn now report?

Carl C. Icahn and affiliated entities report beneficial ownership of 13,426,451 Viskase common shares, equal to 93.7% of the company. This percentage is based on 14,331,713 shares outstanding as of March 26, 2026, as reported to the group.

How did Icahn’s group increase its stake in Viskase (ENZN) in this amendment?

The Icahn group increased its position through merger-related equity exchanges. They swapped 39,277 preferred shares for 5,658,396 Viskase common shares and received 7,407,489 Viskase shares in exchange for 150,810,078 Viskase Companies, Inc. shares at the merger closing.

What merger is referenced in the Viskase (ENZN) Schedule 13D/A Amendment No. 19?

The amendment references the completed merger between Viskase Holdings, Inc. and Viskase Companies, Inc.. The transaction closed on March 26, 2026 under the merger agreement, with Icahn-affiliated entities receiving Viskase shares in exchange for their Viskase Companies, Inc. holdings.

What is the total number of Viskase shares outstanding cited in the filing?

The filing states that Viskase Holdings, Inc. had 14,331,713 common shares outstanding as of March 26, 2026. The reported 93.7% beneficial ownership by Icahn entities is calculated based on this outstanding share count.

Which board changes at Viskase (ENZN) are disclosed in this Schedule 13D/A?

The document notes that Robert Flint, Colin Kwak, and Dustin DeMaria were appointed to Viskase’s board of directors at the merger closing. All three are described as executives or professionals affiliated with Icahn Enterprises or Icahn Capital LP.

Did Icahn entities report other recent trades in Viskase shares besides the merger exchanges?

The amendment states that, apart from the transactions described in Item 4, none of the reporting persons effected any transactions in Viskase common shares during the past 60 days. The only reported activity is tied directly to the merger and related agreements.