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 23, 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 23, 2021, Ecolab Inc. (the “Company”) issued a news release announcing the early tender results of its previously announced offers to exchange (the “Exchange Offers”) its outstanding 5.500% Notes due 2041, 3.950% Notes due 2047, 3.700% Notes due 2046 and 4.800% Notes due 2030 for up to $500 million aggregate principal amount of its 2.750% Notes due 2055 and extension of the deadline to receive the early participation amount. A copy of the news release is filed as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference. ​ In addition, on August 23, 2021, the Company issued a news release announcing the pricing terms of the Exchange Offers. A copy of the news release is filed as Exhibit 99.2 to this Current Report on Form 8-K 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 23, 2021, announcing early tender results of Exchange Offers and extension of the deadline to receive the early participation amount. ​ Filed herewith electronically. ​ ​ ​ ​ ​ ​ ​ ​ ​ (99.2) ​ Ecolab Inc. News Release dated August 23, 2021, announcing pricing terms of Exchange Offers. ​ 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 24, 2021 By: /s/ David F. Duvick ​ ​ David F. Duvick ​ ​ Assistant Secretary ​ ​ 3