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

(Amendment No. 35)

SOUTHWEST GAS HOLDINGS, INC.

(Name of Subject Company)

IEP UTILITY HOLDINGS LLC

ICAHN ENTERPRISES HOLDINGS L.P.

ICAHN ENTERPRISES L.P.

ICAHN ENTERPRISES G.P. INC.

BECKTON CORP.

CARL C. ICAHN

(Names of Filing Persons) (Offerors))

Common Stock, par value $1.00 per share

(Title of Class of Securities)

844895102

(CUSIP Number of Class of Securities)

Jesse Lynn, Esq.

Icahn Enterprises L.P.

16690 Collins Avenue, Suite PH-1

Sunny Isles Beach, FL 33160

(305) 422-4100

(Name, Address, and Telephone Number of Person Authorized to Receive Notices and Communications on Behalf of Filing Persons)

CALCULATION OF FILING FEE

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

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:

This Amendment No. 35 (this “Amendment”) amends and supplements the Tender Offer Statement on Schedule TO, originally filed with the Securities and Exchange Commission (the “SEC”) on October 27, 2021 (as hereby amended and supplemented and together with any subsequent amendments and supplements thereto, this “Schedule TO”), which relates to the tender offer by IEP Utility Holdings LLC, a Delaware limited liability company (the “Offeror”), to purchase any and all of the issued and outstanding shares of the common stock, par value $1.00 per share (the “Common Stock”), of Southwest Gas Holdings, Inc., a Delaware corporation (the “Company” or “Southwest Gas”), including the associated rights issued pursuant to the Rights Agreement, dated October 10, 2021 (as it may be amended from time to time, the “Rights Agreement”), between the Company and Equiniti Trust Company, as rights agent, that are issued and outstanding (the “Rights” and, together with the Common Stock, the “Shares”), for $82.50 per Share in cash, without interest, less any applicable withholding taxes (the “Offer Price”), upon the terms set forth in the Offer to Purchase, dated October 27, 2021 (the “Offer to Purchase”), the related letter of transmittal (the “Letter of Transmittal”), the Notice of Guaranteed Delivery (the “Notice of Guaranteed Delivery”), the Supplement to the Offer to Purchase, dated December 7, 2021 (the “December Supplement”), the Supplement to the Offer, dated May 9, 2022 (“May Supplement”), the Revised Letter of Transmittal (the “Revised Letter of Transmittal”), the Revised Notice of Guaranteed Delivery (the “Revised Notice of Guaranteed Delivery”), and the other related materials, as each may be amended or supplemented from time to time, constitutes the “Offer”.

This Amendment is being filed to amend and supplement the Schedule TO. Except as amended hereby to the extent specifically provided herein, all terms of the Offer and all other disclosures set forth in the Schedule TO and the Exhibits thereto remain unchanged and are hereby expressly incorporated into this Amendment by reference. Capitalized terms used and not otherwise defined in this Amendment shall have the meanings assigned to such terms in the Schedule TO and the Offer to Purchase.

The Schedule TO is hereby amended and supplemented as follows:

Items 1 through Item 11

1. Items 1 through 11 of the Schedule TO are hereby amended and supplemented by adding the following:

“The Offer and the withdrawal rights expired as scheduled at midnight, New York City time, on Friday, May 20, 2022. Continental Stock Transfer & Trust Company, the depositary for the Offer has advised the Offeror that, as of such time, a total of 2,213,597 Shares were validly tendered and not properly withdrawn, representing approximately 3.1% of the outstanding Shares (based on 66,852,050 Shares outstanding as of April 29, 2022, as disclosed by the Company in its Form 10-Q for the quarterly period ended March 31, 2022). Of the Shares tendered, 726,010 Shares were tendered pursuant to guaranteed delivery procedures. Promptly after the Expiration Date, all Shares that were validly tendered and not properly withdrawn pursuant to the Offer have been accepted for payment by the Offeror. The Offeror will promptly pay for all such Shares in accordance with the terms of the Offer. On May 23, 2022, the Offeror issued a press release announcing the expiration and results of the Offer. The full text of the press release is attached as Exhibit (a)(1)(YY) hereto and is incorporated herein by reference.”

Item 12. Exhibits.

Item 12 of the Schedule TO is hereby amended and supplemented by adding the following exhibits thereto:

SIGNATURES

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