Anthropic sues Abnormal over trademark; Abnormal rejects the claims

What's the deal? On 1 July 2026, Anthropic filed a lawsuit against Abnormal SecurityDealroom has a profile for this one. Try Dealroom →, alleging unfair competition and trademark infringement. Anthropic claims Abnormal's slash-based "/\\" logo is confusingly similar to its own "A\\" mark and that Abnormal copied its brand to mislead security customers. The complaint seeks disgorgement of "all revenues, earnings, profits, compensation, and benefits".

Abnormal's response. Founder and CEO Evan ReiserDealroom has a profile for this one. Try Dealroom → rejected the claims in a public blog post and on X, calling the suit "surprising and disappointing". He states that Abnormal was founded in 2018 — three years before Anthropic — that the abnormal.ai domain was registered and used with early customers at that time, and that the current slash wordmark was designed by agency ALINE in April 2021, before Claude existed. Reiser says no customer has ever confused the two companies and that Anthropic does not hold a registered trademark granting a monopoly over A/slash designs in cybersecurity.

Product and customer impact. Reiser emphasised there is no security risk, product change, or change to customer protection. He notes Abnormal builds its own specialised behavioural AI models for threat detection and does not rely on Claude or any third-party AI for autonomous detection and response, though it uses Claude among internal productivity tools. Abnormal says it protects more than 25% of the Fortune 500 plus government organisations at city, state and federal level.

Read more: Abnormal blog · Evan Reiser on X