Anthropic on Monday began rolling out early API access to Claude 4 for select enterprise customers, the San Francisco-based AI safety company announced, marking its most aggressive commercial move yet in its intensifying rivalry with OpenAI. The release targets the business-to-business segment, where Anthropic has seen surging spending in recent months and where industry analysts say it is closing the gap with its larger competitor.

The company published internal and third-party benchmark results showing Claude 4 outperforming OpenAI's GPT-4o on SWE-bench, a widely watched software engineering evaluation, as well as on multi-step reasoning tasks commonly required in legal, financial, and biomedical workflows. Anthropic executives said the gains reflect a new training methodology that prioritises instruction-following reliability over raw parameter count.

The move comes as enterprise AI procurement has become a fierce battleground. According to procurement data cited by multiple industry observers, Anthropic's share of business AI spending has been rising steadily through early 2026, driven partly by workflow automation tools that developers have built using Claude's existing API. Reports this weekend of individuals halving their working hours using Claude-powered automation appeared to validate the company's consumer narrative, but Monday's release is squarely aimed at corporate IT and developer teams.

OpenAI is expected to respond with updated GPT-4o performance data and may accelerate its own enterprise pricing announcements scheduled for later in April. Microsoft, which holds exclusive cloud-distribution rights to OpenAI models through Azure, declined to comment on whether its enterprise licensing terms would be adjusted in response to Anthropic's push.

AnthropicCEO Dario Amodei framed the release as a milestone in the company's mission to build reliably safe and commercially viable AI. 'We believe the safest model should also be the most capable,' Amodei said in a prepared statement. Enterprise pricing for Claude 4 API access starts at a premium tier above current Claude 3.5 rates, with volume discounts available for customers committing to annual contracts.