8-K

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): March 17, 2026

CALUMET, INC.

(Exact name of registrant as specified in its charter)

1060 N Capitol Ave

Suite 6-401

Indianapolis, Indiana 46204

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code (317) 328-5660

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:

Securities Registered Pursuant to Section 12(b) of the Act:

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. ☐

On March 17, 2026, Calumet Specialty Products Partners, L.P. (the “Partnership”) and Calumet Finance Corp. (“Finance Corp.” and, together with the Partnership, the “Issuers”), each a subsidiary of Calumet, Inc. (the “Company”), issued $150.0 million aggregate principal amount of the Issuers’ 9.75% Senior Notes due 2031 (the “Additional Notes”) in a private placement conducted pursuant to Rule 144A and Regulation S under the Securities Act of 1933, as amended (the “Securities Act”). The Additional Notes were issued at 105% of par, plus accrued interest from January 12, 2026, for net proceeds of approximately $154.9 million, after deducting the initial purchasers’ discount, estimated offering expenses and accrued interest. The Company intends to use the net proceeds from the offering of the Additional Notes to repay borrowings outstanding under the Company’s revolving credit facility.

The Additional Notes were issued under the Indenture, dated as of January 12, 2026 (the “Indenture”), among the Issuers, the guarantors party thereto and Wilmington Trust, National Association, as trustee. The Additional Notes constitute a further issuance of the Issuers’ 9.75% Senior Notes due 2031, of which $405.0 million in aggregate principal amount were issued on January 12, 2026 (the “Existing Notes” and, together with the Additional Notes, the “Notes”). The Additional Notes form a single series with, and have the same terms (other than the initial offering price) as, the Existing Notes. The Notes will mature on February 15, 2031. Interest on the Notes is payable semi-annually in arrears on February 15 and August 15 of each year, beginning on August 15, 2026. The Notes are guaranteed on a senior unsecured basis by the Company, Calumet GP, LLC, the general partner of the Partnership, and all of the Partnership’s existing subsidiaries (other than Finance Corp., the Partnership’s unrestricted subsidiaries, Montana Renewables Holdings LLC and Montana Renewables, LLC, and certain immaterial restricted subsidiaries).

For a description of the Indenture and the Notes, please read the Company’s Current Report on Form 8-K filed with the Securities and Exchange Commission on January 12, 2026. A copy of the Indenture and the form of Notes are filed as Exhibit 4.1 and Exhibit 4.2, respectively, to such Current Report on Form 8-K and are incorporated herein by reference.

The information set forth in Item 1.01 of this Current Report on Form 8-K is incorporated by reference into this Item 2.03.

On March 17, 2026, the Company issued a press release announcing the consummation of the offering of the Additional Notes described in Item 1.01 of this Current Report on Form 8-K, a copy of which is attached hereto as Exhibit 99.1 and incorporated herein by reference.

The information in this Item 7.01, including Exhibit 99.1, is being furnished and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section and shall not be deemed to be incorporated by reference into any registration statement or other document filed pursuant to the Securities Act, regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such filing.

This Current Report on Form 8-K includes “forward-looking statements” within the meaning of federal securities laws. Such forward-looking statements are subject to a number of risks and uncertainties, many of which are beyond the Company’s control. All statements, other than historical facts included in this Current Report on Form 8-K, are forward-looking statements. All forward-looking statements speak only as of the date of this Current Report on Form 8-K. Although the Company believes that the plans, intentions and expectations reflected in or suggested by the forward-looking statements are reasonable, there is no assurance that these plans, intentions or expectations will be achieved. Therefore, actual outcomes and results could materially differ from what is expressed, implied or forecast in such statements.

(d) Exhibits

SIGNATURES

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.

EX-99.1

Exhibit 99.1

Calumet Completes Offering of $150 Million of Additional 9.75% Senior Notes due 2031

INDIANAPOLIS, March 17, 2026 /PRNewswire/ — Calumet, Inc. (NASDAQ: CLMT) (the “Company” or “Calumet”) today announced that its wholly owned subsidiaries, Calumet Specialty Products Partners, L.P. (the “Partnership”) and Calumet Finance Corp. (together with the Partnership, the “Issuers”), closed their private placement (the “Offering”) under Rule 144A and Regulation S under the Securities Act of 1933, as amended, of $150 million in aggregate principal amount of 9.75% Senior Notes due 2031 (the “Additional Notes”). The Additional Notes were issued at 105% of par, plus accrued interest from January 12, 2026, for net proceeds of approximately $154.9 million, after deducting the initial purchasers’ discount, estimated offering expenses and accrued interest.

As previously announced, Calumet intends to use the net proceeds from the Offering to repay outstanding borrowings under its revolving credit facility immediately. The Additional Notes constitute a further issuance of the Issuers’ 9.75% Senior Notes due 2031, of which $405 million in aggregate principal amount were issued on January 12, 2026 (the “Existing Notes”). The Additional Notes form a single series with, and have the same terms (other than the initial offering price) as, the Existing Notes.

“Following our strong financial and operational performance in 2025, our priorities remain clear: continue to generate strong cash flow in a favorable margin environment while unlocking additional value at Montana Renewables as we advance our MaxSAF^®^ 150 expansion,” said David Lunin, CFO. “This transaction builds on the success of our notes issuance earlier this year, with proceeds used to immediately reduce our revolver, providing ample flexibility in what’s expected to continue as a volatile and highly profitable commodity environment. Ultimately, we expect to use the additional liquidity provided by this offering to reduce our 2028 notes when the call premium steps down in July.”

About Calumet

Calumet, Inc. (NASDAQ: CLMT) manufactures, formulates and markets a diversified slate of specialty branded products and renewable fuels to customers across a broad range of consumer-facing and industrial markets. Calumet is headquartered in Indianapolis, Indiana and operates twelve facilities throughout North America.

Cautionary Statement Regarding Forward-Looking Statements

Certain statements and information in this press release may constitute “forward-looking statements.” The words “will,” “may,” “intend,” “believe,” “expect,” “outlook,” “forecast,” “anticipate,” “estimate,” “continue,” “plan,” “should,” “could,” “would,” or other similar expressions are intended to identify forward-looking statements, which are generally not historical in nature. The statements discussed in this press release that are not purely historical data are forward-looking statements, including, but not limited to, the statements regarding the use of proceeds from the Offering. These forward-looking statements are based on our current expectations and beliefs concerning future developments and their potential effect on us. While our management considers these assumptions to be reasonable, they are inherently subject to

significant business, economic, competitive, regulatory and other risks, contingencies and uncertainties, most of which are difficult to predict and many of which are beyond our control. Accordingly, our actual results may differ materially from the future performance that we have expressed or forecast in our forward-looking statements. For additional information regarding known material risks, uncertainties and other factors that can affect future results, please see our filings with the Securities and Exchange Commission (“SEC”), including the risk factors and other cautionary statements in the latest Annual Report on Form 10-K of the Company and other filings with the SEC by the Company. We undertake no obligation to publicly update or revise any forward-looking statements after the date they are made, whether as a result of new information, future events or otherwise, except to the extent required by applicable law.

SOURCE Calumet, Inc.

For further information: Investors: John Kompa 317-957-5237; Public Relations: Media Oakes 317-957-5319

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