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424B5 1 tm2613881-1_424b5.htm 424B5 tm2613881-1_424b5 - none - 6.5812274s

The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell the securities and are not soliciting an offer to buy the securities in any jurisdiction where the offer or sale is not permitted.

Filed Pursuant to Rule 424(b)(5)

Registration No. 333-293635

Subject to Completion
Preliminary Prospectus Supplement dated May 19, 2026

PROSPECTUS SUPPLEMENT
(To Prospectus dated February 23, 2026)

Ecolab Inc.

$ Floating Rate Notes due 20
$ % Notes due 20
$ % Notes due 20
$ % Notes due 20
$ % Notes due 20

Ecolab Inc. is offering $ aggregate principal amount of floating rate notes due 20 (the “floating rate notes”), $ aggregate principal amount of % notes due 20 (the “20 notes”), $ aggregate principal amount of % notes due 20 (the “20 notes”), $ aggregate principal amount of % notes due 20 (the “20 notes”) and $ aggregate principal amount of % notes due 20 (the “20 notes” and, together with the floating rate notes, the 20 notes, the 20 notes and the 20 notes, the “notes”). The 20 notes, the 20 notes, the 20 notes and the 20 notes are collectively referred to as the “fixed rate notes.” The floating rate notes will bear interest at a floating rate equal to Compounded SOFR (as defined herein) plus %, subject to the provisions set forth under “Description of the Notes — Interest — Floating Rate Notes;” provided, however, that the minimum interest rate on the floating rate notes will not be less than 0.000%. The floating rate notes will mature on , . The 20 notes will bear interest at a rate of % per year and will mature on , . The 20 notes will bear interest at a rate of % per year and will mature on , . The 20 notes will bear interest at a rate of % per year and will mature on , . The 20 notes will bear interest at a rate of % per year and will mature on , . Interest on the floating rate notes will be payable quarterly in arrears on , , and of each year starting on , 2026. Interest on the fixed rate notes will be payable semi-annually in arrears on and of each year, beginning , 2026.

We may redeem the fixed rate notes of any series at our option, in whole at any time or in part from time to time, at the applicable redemption prices described under “Description of the Notes — Optional Redemption.” The floating rate notes will not be redeemable prior to maturity, except pursuant to a special mandatory redemption as described below. If a change of control repurchase event as described herein occurs with respect to a series of notes, unless we have exercised our option to redeem the notes of that series, we will be required to offer to repurchase the notes of that series at the price described under “Description of the Notes — Offer to Repurchase upon a Change of Control Repurchase Event.”

On March 20, 2026, we entered into a definitive agreement (the “Merger Agreement”) to acquire Frigeo Holdings LLC (“CoolIT Systems” and such transaction, the “CoolIT Systems Acquisition”). We intend to use a portion of the net proceeds from this offering to fund the CoolIT Systems Acquisition. See “Use of Proceeds.”

This offering is not contingent on the completion of the CoolIT Systems Acquisition, which, if completed, will occur subsequent to the completion of this offering. However, if (i) the CoolIT Systems Acquisition is not completed on or prior to the later of (x) September 16, 2026 or (y) such later date to which the end date under the Merger Agreement as in effect on the closing date of this offering may be extended in accordance with the terms thereof (such later date, the “Special Mandatory Redemption End Date”), (ii) prior to the Special Mandatory Redemption End Date, the Merger Agreement is terminated or (iii) we otherwise notify the trustee that we will not pursue the completion of the CoolIT Systems Acquisition, we will be required to redeem the floating rate notes, the 20 notes, the 20 notes and the 20 notes (collectively, the “SMR notes”), at a special mandatory redemption price equal to 101% of the principal amount of the SMR notes to be redeemed plus accrued and unpaid interest thereon to, but excluding the Special Mandatory Redemption Date (as defined herein). See “Description of the Notes — Special Mandatory Redemption.”

The notes will be our senior unsecured obligations and will rank equally in right of payment with all of our other senior indebtedness from time to time outstanding. The notes of each series will be issued only in registered form in denominations of $2,000 and integral multiples of $1,000 in excess thereof.

Investing in the notes involves risks that are described under “Risk Factors” beginning on page S-6 of this prospectus supplement and the risks discussed in the documents we file with the U.S. Securities and Exchange Commission.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the notes or passed upon the adequacy or accuracy of this prospectus supplement or the accompanying prospectus. Any representation to the contrary is a criminal offense.

Public Offering
Price(1)

Underwriting
Discount

Proceeds, before
expenses, to Us

Per Floating Rate Note

Total

Per 20 Note

Total

Per 20 Note

Total

Per 20 Note

Total

Per 20 Note

Total

(1)

Plus accrued interest from , 2026, if settlement occurs after that date.

The notes will not be listed on any securities exchange, and there is currently no public market for the notes.

The underwriters expect to deliver the notes to purchasers in book-entry form only through The Depository Trust Company for the accounts of its participants, including Clearstream Banking S.A. and Euroclear Bank SA/NV, on or about , 2026.

Joint Book-Running Managers

Citigroup

Barclays

BofA Securities

Wells Fargo Securities

The date of this prospectus supplement is , 2026.

	Page
About This Prospectus Supplement		S-ii
Where You Can Find More Information		S-iii
Forward-Looking Statements		S-iv
Prospectus Supplement Summary		S-1
Risk Factors		S-6
Use of Proceeds		S-11
Capitalization		S-12
Description of the Notes		S-13
Certain U.S. Federal Income Tax Considerations		S-33
Underwriting (Conflicts of Interest)		S-38
Legal Matters		S-45
Independent Registered Public Accounting Firm		S-45

	Page
About This Prospectus		2
Ecolab Inc.		2
Risk Factors		3
Forward-Looking Statements		4
Use Of Proceeds		5
Description Of Debt Securities		6
Plan Of Distribution		8
Legal Matters		9
Experts		9
Where You Can Find More Information		9

	As of March 31, 2026
	Actual			As Adjusted
	(in millions)
Cash and cash equivalents		$	519.8		$
Short-term debt:
Commercial paper		$	300.0		$
Notes payable			8.6
Long-term debt, current maturities			1,264.6
Total short-term debt		$	1,573.2		$
Long-term debt:
2.700% senior notes due 2026		$	747.9		$
3.250% senior notes due 2027			482.4
1.650% senior notes due 2027			499.3
5.250% senior notes due 2028			497.4
4.300% senior notes due 2028			497.0
4.800% senior notes due 2030			669.5
1.300% senior notes due 2031			571.0
2.125% senior notes due 2032			646.5
5.000% senior notes due 2035			495.2
5.500% senior notes due 2041			385.3
3.700% senior notes due 2046			197.6
3.950% senior notes due 2047			430.1
2.125% senior notes due 2050			491.8
2.700% senior notes due 2051			840.2
2.750% senior notes due 2055			544.0
Floating rate senior notes due 20 offered hereby			—
% senior notes due 20 offered hereby			—
% senior notes due 20 offered hereby			—
% senior notes due 20 offered hereby			—
% senior notes due 20 offered hereby			—
Finance lease obligations and other			191.9
Long-term debt, current maturities			(1,264.6)
Total long-term debt		$	6,922.5		$
Equity:
Common stock		$	370.2		$
Additional paid-in capital			7,643.7
Retained earnings			13,060.5
Accumulated other comprehensive loss			(1,626.1)
Treasury stock			(9,444.4)
Noncontrolling interest			28.1
Total equity			10,032.0
Total long-term debt and equity		$	16,954.5		$

SEC Form 424B5 filed by Ecolab Inc.