OpenAI and Anthropic are showing significant differences in their projected revenue for 2024. OpenAI is expected to reach $5 billion in annual recurring revenue (ARR), while Anthropic is projected to achieve just under $1 billion ARR. A notable distinction in their revenue sources is that 28% of OpenAI’s revenue comes from API calls, compared to 85% for Anthropic. Anthropic's revenue is reportedly increasing by approximately 1,100% year-over-year, with third-party APIs accounting for 60-75% of sales and AI chatbot subscriptions making up 15%. This substantial growth in API revenue for Anthropic, despite OpenAI's first mover advantage, is seen as a bullish sign for Anthropic.