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ClearSign Technologies (CLIR) ends use of $10.39M ATM prospectus supplement

Filing Impact
(Moderate)
Filing Sentiment
(Neutral)
Form Type
8-K

Rhea-AI Filing Summary

On May 26, 2026, ClearSign Technologies Corporation suspended use of and terminated its existing at-the-market prospectus supplement, which had allowed sales of up to $10.39 million of common stock under a Form S-3 shelf registration.

The company confirms that no shares were sold under this at-the-market facility and the full $10.39 million capacity remained unused when the supplement was terminated. The underlying At The Market Offering Agreement with H.C. Wainwright & Co. remains in effect, but ClearSign will not sell shares under it unless a new prospectus supplement is filed with the SEC.

Positive

  • None.

Negative

  • None.
Item 8.01 Other Events Other
Voluntary disclosure of events the company deems important to shareholders but not covered by other items.
Item 9.01 Financial Statements and Exhibits Exhibits
Financial statements, pro forma financial information, and exhibit attachments filed with this report.
ATM capacity $10.39 million Maximum common stock sales under terminated ATM prospectus supplement
Shelf registration form Form S-3 Shelf registration statement supporting the ATM prospectus supplement
Shelf effectiveness date July 28, 2025 Effective date of Form S-3 shelf registration statement
ATM agreement date July 17, 2025 Date of At The Market Offering Agreement with H.C. Wainwright
ATM suspension date May 26, 2026 Date ClearSign suspended use of and terminated the ATM prospectus supplement
At The Market Offering Agreement financial
"relating to the At The Market Offering Agreement, dated July 17, 2025, by and between the Company and Wainwright"
An at-the-market offering agreement is a contract that lets a company sell newly issued shares directly into the open market through a broker, at whatever price the stock is trading at that moment. For investors this matters because it can increase the number of shares available (which may dilute existing ownership) while providing a flexible, often faster way for the company to raise cash without fixing a price, similar to a vendor selling small batches at current market stalls rather than setting a single fixed price.
prospectus supplement regulatory
"it suspended the use of and terminated the prospectus supplement filed with the Securities and Exchange Commission on July 17, 2025"
A prospectus supplement is an additional document provided alongside a company's main offering details, offering updated or extra information about a specific financial product being sold. It helps investors understand the latest terms, risks, and details of the investment, similar to how an update or revision clarifies or expands on original instructions, ensuring they have current and complete information before making a decision.
shelf registration statement regulatory
"which forms a part of the Company’s “shelf” registration statement on Form S-3"
A shelf registration statement is a document a company files with regulators that allows it to sell shares or bonds quickly when it’s a good time to raise money. It’s like having a pre-approved plan ready so the company can act fast without going through lengthy paperwork each time they want to sell, making fundraising more flexible.
Form S-3 regulatory
"the Company’s “shelf” registration statement on Form S-3 (File No. 333-288736) that became effective on July 28, 2025"
Form S-3 is a legal document companies use to register their stock sales with the government, making it easier and faster for them to raise money by selling shares to investors. It’s like having a pre-approved shopping list that lets a company quickly sell new shares when they need funds, without going through a lengthy approval process each time.
Inline XBRL technical
"Cover Page Interactive Data File (embedded within the Inline XBRL document)"
Inline XBRL is a file format for financial filings that embeds machine-readable data tags directly inside the human-readable report, so the same document can be read by people and parsed by software. For investors it makes extracting, comparing and verifying financial numbers faster and more reliable—like a grocery list where each item also has a barcode—reducing manual errors and speeding up analysis.
false 0001434524 0001434524 2026-05-26 2026-05-26 iso4217:USD xbrli:shares iso4217:USD xbrli:shares
 

 

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): May 26, 2026

 

CLEARSIGN TECHNOLOGIES CORPORATION

(Exact name of registrant as specified in charter)

 

Delaware   001-35521   26-2056298

(State or other jurisdiction of
incorporation)

  (Commission File Number)   (IRS Employer
Identification No.)

 

8023 E. 63rd Place, Suite 101

Tulsa, Oklahoma 74133

(Address of principal executive offices and zip code)

 

(918) 500-7312

(Registrant's telephone number, including area code)

 

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 CFR240.14a-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 240.13(e)-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   CLIR   The Nasdaq Stock Market LLC

 

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 8.01Other Events.

 

On May 26, 2026, ClearSign Technologies Corporation (the “Company”) notified H.C. Wainwright & Co., LLC (“Wainwright”) that it suspended the use of and terminated the prospectus supplement filed with the Securities and Exchange Commission (the “SEC”) on July 17, 2025 (the “ATM Prospectus Supplement”), which forms a part of the Company’s “shelf” registration statement on Form S-3 (File No. 333-288736) that became effective on July 28, 2025, relating to the At The Market Offering Agreement, dated July 17, 2025, by and between the Company and Wainwright (the “ATM Agreement”), covering the sale of up to $10.39 million in shares of its common stock (the “ATM Shares”). Prior to the suspension and termination of the ATM Prospectus Supplement, no ATM Shares had been sold and all $10.39 million remained available for sale pursuant to the ATM Agreement and the ATM Prospectus Supplement.

 

The Company will not make any sales of its shares of common stock pursuant to the ATM Agreement unless and until a new prospectus supplement is filed. Other than the suspension of the sales of the Company’s shares of common stock pursuant to the ATM Agreement and the termination of the related ATM Prospectus Supplement, the ATM Agreement remains in full force and effect.

 

A copy of the ATM Agreement was filed as Exhibit 1.1 to the Company’s Current Report on Form 8-K filed with the SEC on July 18, 2025.

 

Item 9.01Financial Statements and Exhibits.

 

(d) Exhibits.

  

Exhibit No.   Description
104   Cover Page Interactive Data File (embedded within the Inline XBRL document).

  

 

 

 

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.

 

Dated: May 28, 2026

 

  CLEARSIGN TECHNOLOGIES CORPORATION
     
  By: /s/ Colin James Deller
  Name: Colin James Deller
  Title: Chief Executive Officer

 

 

 

FAQ

What did ClearSign Technologies (CLIR) announce regarding its at-the-market offering?

ClearSign Technologies suspended and terminated its existing at-the-market prospectus supplement. This supplement had allowed sales of common stock under a Form S-3 shelf. The underlying At The Market Offering Agreement remains in effect, but no sales will occur unless a new prospectus supplement is filed.

How large was ClearSign Technologies' (CLIR) at-the-market capacity that was terminated?

The terminated prospectus supplement covered up to $10.39 million in common stock. This capacity was established under an at-the-market agreement with H.C. Wainwright & Co. and formed part of a shelf registration statement on Form S-3 effective July 28, 2025.

Did ClearSign Technologies (CLIR) sell any shares under the $10.39 million ATM program?

No, ClearSign did not sell any shares under the terminated ATM prospectus supplement. When the company suspended and terminated the supplement, the full $10.39 million capacity remained unused, meaning no common stock had been issued through that at-the-market facility.

Is ClearSign Technologies' (CLIR) At The Market Offering Agreement still active?

Yes, the At The Market Offering Agreement remains in full force and effect. Only the related prospectus supplement was suspended and terminated. ClearSign states it will not sell common shares under the agreement unless and until it files a new prospectus supplement with the SEC.

Which filing originally established ClearSign Technologies' (CLIR) ATM capacity?

The capacity was tied to a prospectus supplement filed on July 17, 2025. This supplement formed part of ClearSign’s shelf registration statement on Form S-3, file number 333-288736, which became effective on July 28, 2025, supporting at-the-market sales of common stock.

Filing Exhibits & Attachments

3 documents