Company Update

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ​ FORM 8-K ​ CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 ​ Date of Report (Date of earliest event reported) August 9, 2021 ​ ECOLAB INC. (Exact name of registrant as specified in its charter) ​ ​ ​ ​ ​ ​ Delaware ​ 1-9328 ​ 41-0231510 (State or other jurisdiction of incorporation) ​ (Commission File No.) ​ (IRS Employer Identification No.) ​ ​ ​ ​ ​ ​ 1 Ecolab Place , Saint Paul , Minnesota ​ ​ ​ 55102 (Address of principal executive offices) ​ ​ ​ (Zip Code) ​ ​ ​ ​ Registrant’s telephone number, including area code  1- 800 - 232-6522 ​ (Not applicable) (Former name or former address, if changed since last report.) ​ Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below): ​ ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ​ ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ​ ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ​ ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) ​ Securities registered pursuant to Section 12(b) of the Act: ​ ​ ​ ​ ​ ​ ​ ​ Title of each class ​ Trading symbol(s) ​ Name of each exchange on which registered Common Stock, $1.00 par value ​ ECL ​ New York Stock Exchange 2.625% Euro Notes due 2025 ​ ECL 25 ​ New York Stock Exchange 1.000% Euro Notes due 2024 ​ ECL 24 ​ New York Stock Exchange ​ Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company ☐ ​ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐ ​ ​ ​ ​ Item 8.01 Other Events . ​ On August 9, 2021, Ecolab Inc. (the “Company”) issued a news release announcing that it commenced an offer to exchange its outstanding 5.500% Notes due 2041, 3.950% Notes due 2047, 3.700% Notes due 2046 and 4.800% Notes due 2030 for a combination of cash and up to $500 million aggregate principal amount of the Company’s 2.750% Notes due 2055 (the “New Notes”). The New Notes will be a further issuance of, and in addition to, the Notes due 2055 that the Company expects to issue for cash on August 18, 2021, in the aggregate principal amount of $300 million. A copy of the news release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. ​ ​ Item 9.01 Financial Statements and Exhibits . ​ ​ ​ ​ ​ ​ ​ (d) Exhibits. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exhibit No. ​ Description ​ Method of Filing ​ ​ ​ ​ ​ ​ ​ ​ ​ (99.1) ​ Ecolab Inc. News Release dated August 9, 2021. ​ Filed herewith electronically. ​ ​ ​ ​ ​ ​ ​ ​ ​ (104) ​ Cover Page Interactive Data File. ​ Embedded within the Inline XBRL document. ​ ​ ​ ​ 2 ​ ​ SIGNATURE ​ Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. ​ ​ ​ ​ ​ ECOLAB INC. ​ ​ ​ ​ Date: August 10, 2021 By: /s/ David F. Duvick ​ ​ David F. Duvick ​ ​ Assistant Secretary ​ ​ 3