Announcement PDF Immuron Updates At-The-Market Funding Facility Melbourne, Australia – 27 October 2026: Immuron Limited (ASX: IMC; NASDAQ: IMRN), an Australian- based and globally integrated biopharmaceutical company, advises that it has filed a Prospectus Supplement with the U.S. Securities and Exchange Commission in connection with its existing At-The-Market ("ATM") offering facility with H.C. Wainwright & Co., LLC. Highlights • Immuron has updated the capacity available under its existing ATM facility with H.C. Wainwright & Co., LLC to an aggregate offering amount of approximately US$2.0 million. • The ATM facility continues to provide the Company with a flexible and efficient mechanism to access capital, if and when required. • Immuron retains sole discretion regarding the use of the ATM facility, including the timing of any issuances, the number of American Depositary Shares ("ADSs") issued and the minimum issue price of any ADSs. • The ATM facility operates within the Company's available securities issuance capacity and applicable regulatory requirements. ATM Facility Update As previously disclosed, on 2 July 2024, the Company entered into an At-The-Market Offering Agreement (the ATM Agreement) with H.C. Wainwright & Co., LLC. Under the ATM Agreement, the Company may offer and sell ADSs representing ordinary shares from time to time at its sole discretion. The Company has determined to reduce the maximum aggregate offering amount available under the ATM Agreement to approximately US$2,006,769. The revised facility amount reflects the Company's ongoing capital management strategy and current funding requirements while preserving the flexibility to access capital efficiently should the need arise. The Company believes that maintaining the ATM facility provides an important source of strategic and financial flexibility and allows it to respond efficiently to operational requirements, development opportunities and market conditions. A copy of the Prospectus Supplement and related documents accompanies this announcement. This announcement has been authorised for release by the Board of Directors of Immuron Limited. - - - END - - - COMPANY CONTACT: Steven Lydeamore Chief Executive Officer steve@immuron.com About Immuron Immuron Limited (ASX: IMC, NASDAQ: IMRN), is an Australian biopharmaceutical company focused on developing and commercializing orally delivered targeted polyclonal antibodies for the treatment of infectious diseases. About Travelan® Travelan® is an orally administered passive immunotherapy that prophylactically reduces the likelihood of contracting travelers’ diarrhea, a digestive tract disorder that is commonly caused by pathogenic bacteria and the toxins they produce. Travelan® is a highly purified tabletized preparation of hyper immune bovine antibodies and other factors, which when taken with meals bind to diarrhea-causing bacteria and prevent colonization and the pathology associated with travelers’ diarrhea. In Australia, Travelan® is a listed medicine on the Australian Register for Therapeutic Goods (AUST L 106709) and is indicated to reduce the risk of Travelers’ Diarrhea, reduce the risk of minor gastro-intestinal disorders and is antimicrobial. In Canada, Travelan® is a licensed natural health product (NPN 80046016) and is indicated to reduce the risk of Travelers’ Diarrhea. In the U.S., Travelan® is sold as a dietary supplement for digestive tract protection. Travelers’ diarrhea (TD) TD is generally defined as the passage of ≥ 3 unformed stools per 24 hours plus at least one additional symptom (such as nausea, vomiting, abdominal cramps, fever, blood/mucus in the stools, or fecal urgency) that develop while abroad or within 10 days of returning from any resource-limited destinations (Leung et al., 2006). Diarrhea continues to be the most frequent health problem among travelers to destinations in lower- and middle-income regions (Steffen, 2017). Deployed US military personnel, essentially representing a long-term traveller population, are particularly affected given their population dynamics and the context in which they seek care and treatment (Connor et al., 2012). Diarrhea is the leading infectious disease threat to the overall health and preparedness of deployed US armed forces, with diarrheagenic E. coli, Campylobacter spp., and Shigella spp. among the most commonly reported etiologies (Riddle et al., 2006). Immuron Platform Technology Immuron’s proprietary technology is based on polyclonal immunoglobulins (IgG) derived from engineered hyper-immune bovine colostrum. Immuron has the capability of producing highly specific immunoglobulins to any enteric pathogen and our products are orally active. Bovine IgG can withstand the acidic environment of the stomach and is resistant to proteolysis by the digestive enzymes found in the Gastrointestinal (GI) tract. Bovine IgG also possesses this unique ability to remain active in the human GI tract delivering its full benefits directly to the bacteria found there. The underlying nature of Immuron’s platform technology enables the development of medicines across a large range of infectious diseases. The platform can be used to block viruses or bacteria at mucosal surfaces such as the Gastrointestinal tract and neutralize the toxins they produce. IMM-124E (Travelan®) IMM-124E was developed using Immuron’s platform technology. IMM-124E is produced from the colostrum of birthing cattle that have been immunised during pregnancy with a vaccine containing the outer antigens of multiple human derived ETEC. A total of 13 ETEC strains are used in the vaccine to produce high levels of antibodies against selected surface antigens from the most common strains of ETEC. (Otto et al., 2011) The resultant hyperimmune colostrum IMM-124E from ETEC vaccinated cows contains significant levels of polyclonal antibodies specific for ETEC antigens LPS, CFA-I and Flagellin (Sears et al., 2017). The antibodies produced in IMM-124E have been found to have a stronger binding and neutralizing activity (than the antibodies of unvaccinated cattle) against a wide range of LPS antigens including both the variable O-polysaccharide region and the preserved oligosaccharide core ‘R’ region of LPS from the 13 serotypes used in the ETEC vaccine. IMM-124E is manufactured into a tablet form referred to as Travelan®. IMM-529 Immuron is developing IMM-529 as an adjunctive therapy in combination with standard of care antibiotics for the prevention and/or treatment of recurrent Clostridioides difficile infection (CDI). IMM-529 antibodies targeting Clostridioides difficile (C. diff) may help to clear CDI infection and promote a quicker re-establishment of normal gut flora, providing an attractive oral preventative for recurrent CDI. Immuron is collaborating with Dr. Dena Lyras and her team at Monash University, Australia to develop vaccines to produce bovine colostrum-derived antibodies. Dairy cows were immunised to generate hyperimmune bovine colostrum (HBC) that contains antibodies targeting three essential C. diff virulence components. IMM-529 targets Toxin B (TcB), the spores and the surface layer proteins of the vegetative cells. This unique 3-target approach has yielded promising results in pre-clinical infection and relapse models, including (1) Prevention of primary disease (80% P =0.0052); (2) Protection of disease recurrence (67%, P <0.01) and (3) Treatment of primary disease (78.6%, P<0.0001; TcB HBC). Importantly IMM-529 antibodies cross-react with whole cell lysates of many different human strains of C. diff including hypervirulent strains. To our knowledge, IMM-529 is, to date, the only investigational drug that has shown therapeutic potential in all three phases of the disease (Hutton et al., 2017). ProIBS® Immuron has an exclusive distribution agreement with Calmino goup AB for the territories of Australia and New Zealand for ProIBS®. ProIBS® - to help patients treat IBS symptoms ProIBS® is a certified medical device for the treatment of IBS symptoms such as abdominal pain, bloating and unsettled bowel movements (diarrhoea and/or constipation). ProIBS® contains AVH200®, derived from the plant Aloe barbadensis. Mill. AVH200® has gel forming components which support the intestinal mucosal barrier. As IBS is known to affect individuals for a long period of time, it is essential to have a treatment appropriate for long- term use –as ProIBS® is. The product is safe, and no interactions with other medications are known. Science-driven innovative Calmino group AB, the developer of ProIBS®, conducted a usability study among 1,003 users. PROIBS® was helpful for 94% of them. 91% of the users experienced an improvement in daily life and 98% would recommend PROIBS® to someone else. To learn more please check: www.proibs.eu. Irritable bowel syndrome (IBS) is a common condition where you experience symptoms related to your digestive system. This is sometimes linked to certain foods, lifestyle habits and stress levels or mood. IBS affects around 3 out of every 10 people. Females are more likely than males to be affected. Some key symptoms of IBS include: abdominal pain or discomfort; stomach bloating and wind; chronic diarrhoea or constipation, or alternating between the two.(healthdirect.gov.au) According to available data, the IBS treatment market in Australia is estimated to be a part of the broader "Digestives & Intestinal Remedies" market, generating a revenue of around AU$221.14 million in 2025, with a projected annual growth rate of 3.28%.(Statista) References Connor P, Porter CK, Swierczewski B and Riddle MS. Diarrhea during military deployment: current concepts and future directions. Curr Opin Infect Dis. 25(5): 546-54; 2012. Hutton, M.L., Cunningham, B.A., Mackin, K.E. et al. Bovine antibodies targeting primary and recurrent Clostridium difficile disease are a potent antibiotic alternative. Sci Rep 7, 3665 (2017). https://doi.org/10.1038/s41598-017-03982-5 Leung AK, Robson WL, Davies HD. Travelers’ diarrhea. Adv Ther. Jul-Aug; 23(4): 519-27; 2006 Otto W, Najnigier B, Stelmasiak T and Robins-Browne RM. Randomized control trials using a tablet formulation of hyperimmune bovine colostrum to prevent diarrhea caused by enterotoxigenic Escherichia coli in volunteers Scandinavian Journal of Gastroenterology 46: 862– 868; 2011. Riddle MS, Sanders JW, Putnam SD, and Tribble DR. Incidence, etiology, and impact of diarrhea among long-term travelers’ (US military and similar populations): A systematic review. American Journal of Tropical Medicine and Hygiene. 74(5): 891-900; 2006. Sears KT, Tennant SM, Reymann MK, Simon R, Konstantopolos N, Blackwelder WC, Barry EM and Pasetti MF. Bioactive Immune Components of Anti-Diarrheagenic Enterotoxigenic Escherichia coli Hyperimmune Bovine Colostrum products. Clinical and Vaccine Immunology. 24 (8) 1-14; 2017. Steffen R. Epidemiology of travelers' diarrhea. J Travel Med. 24(suppl_1): S2-S5; 2017. For more information visit: https://www.immuron.com.au/ and https://www.travelan.com Subscribe to Immuron’s InvestorHub: Here FORWARD-LOOKING STATEMENTS: This press release may contain “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, each as amended. Such statements include, but are not limited to, any statements relating to our growth strategy and product development programs and any other statements that are not historical facts. Forward-looking statements are based on management’s current expectations and are subject to risks and uncertainties that could negatively affect our business, operating results, financial condition, and stock value. Factors that could cause actual results to differ materially from those currently anticipated include: risks relating to our growth strategy; our ability to obtain, perform under and maintain financing and strategic agreements and relationships; risks relating to the results of research and development activities; risks relating to the timing of starting and completing clinical trials; uncertainties relating to preclinical and clinical testing; our dependence on third-party suppliers; our ability to attract, integrate and retain key personnel; the early stage of products under development; our need for substantial additional funds; government regulation; patent and intellectual property matters; competition; as well as other risks described in our SEC filings. We expressly disclaim any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in our expectations or any changes in events, conditions, or circumstances on which any such statement is based, except as required by law. Filed Pursuant to Rule 424(b)(5) Registration No. 333-280667 PROSPECTUS SUPPLEMENT (To Prospectus dated July 19, 2024) IMMURON LIMITED Up to $2,006,769 American Depositary Shares Representing Ordinary Shares This prospectus supplement amends, supplements, modifies and supersedes, only to the extent indicated herein, certain information contained in our Offering Agreement prospectus dated July 19, 2024, which together with the accompanying base prospectus dated July 19, 2024 contained in our Registration Statement on Form F-3 (Registration No. 333-280667), which we refer to as the prospectus, relating to the offering, issuance, and sale of our American Depositary Shares (each, an “ADS” and, collectively the “ADSs”) representing our ordinary shares that may be issued and sold from time to time under an at- the-market offering agreement dated as of July 2, 2024 (the “Offering Agreement”) between us and H.C. Wainwright & Co., LLC (“Wainwright”). These sales, if any, will be made pursuant to the terms of the Offering Agreement. This prospectus supplement should be read in conjunction with, is not complete without, and may not be delivered or utilized except in connection with, the prospectus, including all supplements thereto and documents incorporated by reference therein. If there is any inconsistency between the information in the prospectus and this prospectus supplement, you should rely on the information in this prospectus supplement. Any information that is modified or superseded in the prospectus shall not be deemed to constitute a part of the prospectus, except as modified or superseded by this prospectus supplement. The aggregate market value of our outstanding ordinary shares held by non-affiliates as of the date of this prospectus supplement is approximately $14,563,418, based on 8,071,202 ADS-equivalents (representing 322,848,081 ordinary shares) outstanding as of the date of this prospectus supplement, of which 7,914,901 ADS-equivalents were held by non-affiliates, and a price per ADS of US$1.84, which was the closing sale price of our ADS on the Nasdaq Capital Market on September 8, 2026. Pursuant to General Instruction I.B.5 of Form F-3, in no event will we sell securities pursuant to this prospectus supplement with a value of more than one-third of the aggregate market value of our ordinary shares held by non-affiliates in any 12 calendar month period, or $4,854,473 as of the date of this prospectus supplement. As of the date of this prospectus supplement, we have sold approximately $2,847,703 of securities pursuant to General Instruction I.B.5 of Form F-3 during the 12 calendar months prior to, and including, the date of this prospectus supplement, and are therefore eligible to sell up to an additional $2,006,769 of our securities pursuant to General Instruction I.B.5 of Form F-3. Pursuant to General Instruction I.B.5 of Form F-3, in no event will we sell securities registered on this registration statement in a public primary offering with a value exceeding more than one-third of the aggregate market value of our voting and non-voting common equity held by non-affiliates in any 12 calendar month period so long as our public float remains below $75 million. We are filing this prospectus supplement to supplement and amend, as of October 23, 2026, the prospectus, as supplemented, to decrease the maximum aggregate offering price of our securities that may be offered, issued and sold under the prospectus, as supplemented and amended by this prospectus supplement, pursuant to the Offering Agreement with Wainwright to approximately $2,006,769. From and after the date hereof, pursuant to General Instruction I.B.5 of Form F-3, we are offering to issue and sell up to approximately $2,006,769 of securities from time to time through Wainwright, acting as our sales agent or principal in accordance with the Offering Agreement. Our ADSs are listed on The Nasdaq Capital Market under the symbol “IMRN.” Each ADS represents 40 of our ordinary shares, no par value per share. On October 22, 2026, the last reported price of our ADSs on The Nasdaq Capital Market was $0.97 per ADS. Our ordinary shares are currently listed on the Australian Securities Exchange, or ASX, under the symbol “IMC.” On October 22, 2026, the last reported price of our ordinary shares on the ASX was A$0.04 per ordinary share. Sales of ADSs, if any, under this prospectus supplement and accompanying prospectus may be made in sales deemed to be “at the market offerings” as defined in Rule 415 under the Securities Act of 1933, as amended, or the Securities Act. Wainwright is not required to sell any specific number or dollar amount of ADSs but will act as a sales agent using commercially reasonable efforts consistent with its normal trading and sales practices, on terms mutually agreed to by Wainwright and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement. We will pay Wainwright a cash commission equal to 3.0% of the gross sales price of the ADSs sold by Wainwright under the Offering Agreement. In connection with the sale of the ADSs on our behalf, Wainwright will be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation paid to Wainwright will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contribution to Wainwright with respect to certain liabilities, including liabilities under the Securities Act. Investing in our securities involves a high degree of risk. Before buying any of our securities, you should carefully consider the risk factors described in “Risk Factors” beginning on page 4 of the Offering Agreement prospectus dated July 19, 2024, and under similar headings in other documents that are incorporated by reference into this prospectus supplement and the prospectus. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense. H.C. Wainwright & Co. The date of this prospectus supplement is October 23, 2026.