[6-K] Opthea Ltd Current Report (Foreign Issuer)

Rhea-AI Filing Summary

Opthea Limited filed a Form 6-K noting it issued a press release announcing its intention to voluntarily delist its American Depositary Shares from the Nasdaq Global Select Market.

The press release, dated October 29, 2025, is furnished as Exhibit 99.1 and is incorporated by reference into Opthea’s Form S-8 (File No. 333-251052). This notice focuses on the planned delisting of Opthea’s ADSs from Nasdaq as described in the press release.

Insights

Equity listings and market structure analyst

Opthea plans to delist ADSs from Nasdaq; a materially negative signal.

Opthea disclosed an intention to voluntarily delist its ADSs from the Nasdaq Global Select Market, as stated in a press release furnished with the 6‑K. This action changes the listing venue status of the ADSs and typically precedes trading moving to alternative markets.

The filing does not provide timing, rationale, or post-delisting trading arrangements in this excerpt. Investor impact depends on subsequent company disclosures and any transition plans described outside this excerpt.

Key artifact: the press release dated October 29, 2025 attached as Exhibit 99.1. Future company materials may detail effective dates, next trading venue, and holder instructions.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN ISSUER

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

OF THE SECURITIES EXCHANGE ACT OF 1934

For the month of October 2025

Commission File No. 001-39621

OPTHEA LIMITED

(Translation of registrant’s name into English)

C/- Prime Company Compliance, Level 9

505 Little Collins Street

Melbourne, VIC 3000

Australia

(Address of registrant’s principal executive office)

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

Form 20-F ☒   Form 40-F ☐

INCORPORATION BY REFERENCE

This Report on Form 6-K and Exhibit 99.1 to this Report on Form 6-K shall be deemed to be incorporated by reference into the registration statement on Form S-8 (File No. 333-251052), of Opthea Limited (“Opthea”) (including any prospectuses forming a part of such registration statement) and to be a part thereof from the date on which this report is filed, to the extent not superseded by documents or reports subsequently filed or furnished.

INFORMATION CONTAINED IN THIS REPORT ON FORM 6-K

Press Release dated October 29, 2025

On October 29, 2025, Opthea Limited issued a press release announcing its intention to voluntarily delist its American Depositary Shares from The Nasdaq Global Select Market.

The full text of the press release is attached as Exhibit 99.1 to this Report on Form 6-K and incorporated herein by reference.

EXHIBIT INDEX

Exhibit		Description
99.1		Opthea Press Release dated October 29, 2025

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, thereto duly authorized.

OPTHEA LIMITED
(Registrant)
By:		/s/ Jeremy Levin
Name:		Jeremy Levin
Title:		Chief Executive Officer

Date: October 30, 2025

FAQ

What did Opthea (OPT) announce in this Form 6-K?

Opthea announced its intention to voluntarily delist its American Depositary Shares from the Nasdaq Global Select Market.

Where can I find the detailed announcement from Opthea (OPT)?

The full text is in the press release dated October 29, 2025, furnished as Exhibit 99.1 to the Form 6-K.

Does the Form 6-K affect Opthea’s existing registration statements?

Yes. The Form 6-K and Exhibit 99.1 are incorporated by reference into Opthea’s Form S-8 (File No. 333-251052).

What securities are impacted by Opthea’s announcement?

The announcement pertains to Opthea’s American Depositary Shares listed on the Nasdaq Global Select Market.

What is the exhibit included with Opthea’s Form 6-K?

The filing includes Exhibit 99.1, titled “Opthea Press Release dated October 29, 2025.”

What is the form type and purpose of this submission by Opthea (OPT)?

It is a Form 6-K furnishing a press release about the company’s plan to voluntarily delist its ADSs from Nasdaq.