Report of Foreign Issuer (6-k)

U.S. SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16 UNDER

THE SECURITIES EXCHANGE ACT OF 1934

For the month of August 2018

Commission File Number: 001-36885

TANTECH HOLDINGS LTD.

Tantech Holdings Ltd.

No. 10 Chen Shan Road, Shuige Industrial Zone

Lishui City, Zhejiang Province 323600

+86-578-226-2305

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F x Form 40-F ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ¨

Explanatory Note:

Changes in Registrant's Certifying Accountant

On August 21, 2018, the Company’s Audit Committee and Board of Directors approved the proposed appointment of Prager Metis CPAs, LLC (“Prager Metis”) as the Company's independent registered public accounting firm, dismissing the Company's previous independent auditors, Friedman LLP (“Friedman”), on the same date.

During the Company’s most recent two fiscal years ended December 31, 2017 and 2016 through the dismissal of Friedman on August 21, 2018, there were no disagreements between us and Friedman on any matter of accounting principles or practices, financial statement disclosure, or auditing scope or procedure, which disagreements, if not resolved to the satisfaction of Friedman, would have caused it to make reference to the subject matter of the disagreements in connection with its report on the Company's consolidated financial statements for such periods. In addition, Friedman’s reports on the financial statements as of and for the years ended December 31, 2017 and 2016 did not contain an adverse opinion or disclaimer of opinion and were not qualified or modified as to uncertainty, audit scope or accounting principles. During the Company’s years ended December 31, 2017 and 2016 through the dismissal of Friedman on August 21, 2018, there were no “reportable events” as that term is defined in Item 16F(a)(1)(v) of Form 20-F.

During the two most recent fiscal years ended December 31, 2017 and 2016 and any subsequent interim period prior to engaging Prager Metis, neither the Company nor anyone on its behalf consulted Prager Metis regarding either (i) the application of accounting principles to any proposed or completed transaction, or the type of audit opinion that might be rendered on the Company’s financial statements, and neither a written report nor oral advice was provided to the Company that Prager Metis concluded was an important factor considered by the Company in reaching a decision as to any accounting, auditing or financial reporting issue; or (ii) any matter that was either the subject of a disagreement (as defined in Item 16F(a)(1)(iv) of Form 20-F and the related instructions to Item 16F of Form 20-F) or a reportable event.

The Company has provided Friedman with a copy of the disclosures the Company is making in this Current Report on Form 6-K and has filing as Exhibit 99.1 the letter from Friedman stating that Friedman agrees or has no basis to agree or disagree with the disclosures made herein.

Exhibits

Exhibit 99.1

Letter from Friedman LLP dated August 23, 2018

SIGNATURES

Pursuant to the requirements of the Securities and Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.