Citigroup Inc. (C  ) has been added to the list of banks preparing Elon Musk's SpaceX initial public offering (IPO), according to Bloomberg. The company is reportedly preparing to confidentially file for an IPO as soon as next month, targeting a June listing that could raise up to $50 billion, and surpassing Saudi Aramco's $29 billion debut in 2019 to become the largest IPO in history.

By filing confidentially, SpaceX can receive SEC feedback and make adjustments before its prospectus becomes public. Discussions are understood to be underway, details remain subject to change, and additional banks may be added.

SpaceX is also considering a dual-class share structure that could give insiders, including Musk, outsized voting power over corporate decisions.

Last month, Musk announced that SpaceX had acquired his artificial intelligence startup xAI. The transaction valued SpaceX at about $1 trillion and xAI at roughly $250 billion, reported Reuters, citing people familiar with the matter.

Bank of America, Goldman Sachs Group, JPMorgan Chase, and Morgan Stanley are all working on the IPO. Meanwhile, Royal Bank of Canada and Mizuho are also understood to be participating in the IPO process, Bloomberg noted.