Arcturus Therapeutics Holdings Inc

Item 1A. Risk Factors.

Our business is subject to various risks, including those described in Item 1A of our Annual Report on Form 10-K for the fiscal year ended December 31, 20245, which we strongly encourage you to review. Except as disclosed below, there have been no material changes from the risk factors described in our Annual Report on Form 10-K for the year ended December 31, 20245 filed with the Commission on March 63, 2025.

A prolonged U.S. federal government shutdown could materially and adversely affect our business, operations, and legal proceedings. 

On October 1, 2025, the federal government of the United States began a shutdown at 12:01 a.m. EDT as a result of congressional failure to pass appropriations legislation for the 2026 fiscal year, which began that day. A 6.

Geopolitical risks associated with ongoing wars and armed continued and prolonged shutdownflicts could materiallyhave and adversely affe impact on our business, operations, financial condition, and legal matters. A federal government shutdown may result in the furlough of federal employees, reduced availability results of government services, and suspension or delay of activities by key agencies that regulate, fund, or interact with our businessoperations, including the SEC, the FDA, the HHS, and the U.S. Patent and Trademark Office. During such periods, review and approval of our filings, applour clinications, and submissions could be delayed, and we may be unable to access or rely upon certain government data or systems. In addition, the Administrative Office of the U.S. Courts and federal judiciary operations rely on appropriated funds and fee-based reserves that may be exhausted in the event of an extended shutdown. If federal court fundl trials.

Geopolitical developments related to ongoing lapses or is limited to essentiglobal functions only, civil litigation, bankruptcy proceedings,conflicts and regulatory enforcement actions involving us or tensions are sour affiliates could be postponed or suspended. Any such delay could impede our abilices of uncertainty to resolve disputes, enforce contractual rights, or obtain timely judicial relief, which and risk, and may have a material advercause effect on our financial position or prospects. Such conditidisruptions could negatively impact our access to financing, timing of capital-raising transactions, and the liquidityto global or trading volume of our securities. Accordingly, the current federregional government shutdown, or uncertainty regarding the continuity of government operatiomarkets, supply chains could have a material adverse effect on our business, results of oor operations, and stock price.

We have filed a lawsuit alleging trade secret misappropriation and breach of contract, and any unfavora in applicable outcome or related proceedings could materially and adversely affect our business, financial condition, results of operations, and reputation.

On September 23, 2025, we filed a lawsuit in the United States District Court for the Southern District of California against AbbVie Inc., Capstan Therapeutics, Inc., and other defendants asserting claims for trade secret misappropriation and breach of contract. The defendants current deadline to respond to our complaint is December 1, 2025, and the court has not set a case schedule. Litigation is inherently uncertain, time-consuming, and costlyregions, including those related to conflicts in the Middle East. We may not prevail on our claims, ahave and the defendants may assert counterclaims against us, including challengescontinue to our intellectual property or allegations of our own misconduct, any of which could result in adverse rulings, monetary judgments, fee or cost awards, or other relief that may be material. Even if we are successful in whole or in part, the litigation could result in substantial expense, divert manaevaluate and engage in activities, including engagements attention and operational resources, disrupt relationships with partners, collaborators, or customer of clinical sites, and require in the disclosure of sensitive information in discovery that could diminish the value of our trade secrets or other confidentialMiddle East. Conflicts information. T the court could deny our requested relief, limit the scope of our asserted rights, or otherwise issue rulings that adversely affect our ability to protect, use, or commercialize our intellectual prMiddle East could disrupt operty and technology. In addition, associated proceedings, including motions practice, discovery disputes, and potential appeals, could be protracted and unpredictable, particularly given that the court has not yet established a case schedule. Any of ations of companies doing business in these outcomes could negatively impact our competitive positio region, delay or impede our research, development, manufacturincluding, or commercialization activities, and result in increased legal and compliance costs in Israel. As a result, this litigation and any related proceedings could materially and adversely affect our business, financial condition, cash flows, and results of operations.

CSL Limitedsny significant changes in the potential separation of CSL Seqirus could disrupt our collaboration and materlitical, economic, financially harm our business.

Reports that CSL Limited intends to separate or spin off its vaccine business, including its subsidiary CSL Seqirus, could disrupt or adversely affect our collaboration, competitive, legal and materially harm our business. We are party to a strategic collaboration with CSL Seqirus for the development and commercialization of mRNA vaccines for COVID-19, influenza and certain other infectious diseases. We cannot 

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pregulatory or redict the timing, terms, structure, or ultimate consummation of any potential separation, and even the announceimbursement or pendency of such a transaction may create uncertainty and execution risk that could adversely affect CSL Seqiruss performance under our agreements and, as a resulconditions where we conduct, our programs, timelines and costs. Forlan to example, a separation could lead to shifting strategic priorities, changes in management focus, or reduced access to corporate resources, capital, manufacturing networks or commercial infrastructure previously available to CSL Seqirus as part of the CSL group. In addipand, our international operation, any standalone entity s may have a different risk profile, capital structure, credit quality, or appetite for development and commercial investment, which could impair its ability or willingnmaterial impact on our business to satisfy funding, diligence, supply, or commerc, financialization obliga conditions or to continue programs that were prioritized prior to the separesults of operations.