UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 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 June 2021

Commission File Number: 001-40504

Tremor International Ltd.

(Translation of registrant’s name into English)

Tremor International Ltd.

82 Yigal Alon Street

Tel Aviv, 6789124, Israel

(Address of principal executive office)

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  ☒            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

On June 30, 2021, Tremor International Ltd. (the “Company”) issued a regulatory news service announcement announcing the publication of the Company’s Annual Report and Accounts for the year ended December 31, 2020 (the “Announcement”). The Announcement is furnished herewith as Exhibit 99.1 to this Report of Foreign Private Issuer on Form 6-K.

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.

Exhibit 99.1

30 June 2021

Tremor International Ltd

(“Tremor” or the “Company”)

Posting of Annual Report and Accounts

Tremor International Ltd (AIM/NASDAQ: TRMR), a global company offering an end-to-end software platform that enables advertisers to reach relevant audiences and publishers to maximize yield on their digital advertising inventory, confirms that its Annual Report and Accounts for the year ended 31 December 2020 have been posted to Shareholders and are now available on the Company’s website at www.tremorinternational.com.

The Company’s Notice of Annual General Meeting will be posted in due course.

For further information please contact:

About Tremor International

Tremor is a global company offering an end to end software advertising platform, operating across three core capabilities - Video, Data and CTV. Tremor’s unique approach is centred on offering a full stack of end-to-end software solutions which provides it with a major competitive advantage within the video advertising ecosystem.

Tremor Video helps advertisers deliver impactful brand stories across all screens through the power of innovative video technology combined with advanced audience data and captivating creative content. Tremor Video’s innovative video advertising technology has offerings in CTV, in-stream, out-stream and in-app.

The media side of Tremor, Unruly, drives real business outcomes in multiscreen advertising. Its programmatic platform efficiently and effectively delivers performance, quality, and actionable data to demand and supply-focused clients and partners. Tremor has a meaningful number of direct integrations with publishers, unique demand relationships with a variety of advertisers and privileged access to News Corp inventory. Unruly connects to the world’s largest DSPs and is compatible with most AdAge top 100 brands.

Tremor is headquartered in Israel and maintains offices throughout the United States, Canada, Europe, Asia-Pacific and Australia and is traded on the London Stock Exchange (AIM: TRMR) and NASDAQ .