June 8 (Reuters) - ChatGPT developer OpenAI filed for a U.S. initial public offering on Monday, joining rival Anthropic in heading to the stock market as investors seek to capitalize on the boom in the artificial intelligence sector.

OpenAI did not disclose the size or terms of the offering, and said the timeline is still being finalized. In a statement, they added, "It may take some time because there are things we want to do that will likely be easier to accomplish given that the company is private."

Reuters had reported that the artificial intelligence giant was targeting a valuation of up to $1 trillion at the start of its IPO, which could happen as early as September.

If it manages to reach this valuation, it will pave the way for three companies with a valuation of at least one trillion dollars to enter the market quickly, and this is seen as the most important test of investors' appetite for technology stocks that have grown significantly in the last ten years.

Elon Musk’s SpaceX was the first to launch, submitting an application for an initial public offering that could be the largest in history, as the company seeks to offer $75 billion worth of shares and reach a valuation of $1.75 trillion.