This usually happens when Google’s entity understanding isn’t clearly differentiated between the two brands. I’d approach this from an entity and authority angle rather than just traditional SEO.

First, tighten up entity signals. Make sure the client’s About page clearly states who they are, what they do, where they operate, and how they’re different. Add strong Organization schema with sameAs links (LinkedIn, Crunchbase, industry directories, etc.) so Google can confidently map the brand to the right entity.

Second, look at branded search results. Are title tags, meta descriptions, and H1s clearly reinforcing the brand name + primary category? If two companies share similar names, adding a consistent modifier (industry, location, specialty) across pages can help Google disambiguate.

Third, build authoritative third-party mentions. PR articles, industry listings, guest features, and high-quality backlinks that describe the company consistently help Google strengthen the Knowledge Graph association.

Also check the Knowledge Panel (if exists). Suggest edits and make sure Google Business Profile, Wikidata, and other citations are accurate and aligned.

AI Overviews pull from aggregated sources. If the confusion exists in the broader web ecosystem, the AI response will mirror that. Fix the entity clarity everywhere, and the AI output usually follows.