San Francisco, Dec 6 : Elon Musk's AI company called xAI is seeking to raise up to $1 billion in equity investments. According to a filing with the US Securities and Exchange Commission (SEC), the Tesla and SpaceX CEO has raised $134.7 million so far for xAI. The $135 million came from four unnamed investors, with the first sale occurring on November 29. The SEC filing noted that xAI will only accept a minimum of $2 million from outside investors. Taking on Sam Altman-run OpenAI's ChatGPT, Musk said last month that xAI's AI chatbot Grok has current information in comparison to traditional GPT models. The xAI 'Grok' AI assistant is being provided to the users as part of X Premium Plus which costs $16 per month via web. 'Grok is an AI modeled after the Hitchhiker's Guide to the Galaxy, so intended to answer almost anything and, far harder, even suggest what questions to ask,' said the xAI team. Grok is designed to answer questions with a bit of wit and has a rebellious streak. Musk was a co-founder of OpenAI but left in 2018 over the company's for-profit shift, and has called ChatGPT 'WokeGPT'. The billionaire launched xAI earlier this year. The team is headed up by Musk and includes team members that have worked at other big names in AI, including OpenAI, Google Research, Microsoft Research, and Google's DeepMind. 'The goal of xAI is to understand the true nature of the universe,' according to the website. /IANS