The funding comes after the aerospace giant hit a $100bn valuation following a secondary share sale in October.
SpaceX has raised $337.4m in equity financing, the rocket company disclosed in a regulatory filing, according to a report in Reuters.
SpaceX, which counts Alphabet and Fidelity Investments among its investors, hit $100bn in valuation following a secondary share sale in October. It had raised about $1.16bn in equity financing in April.
The company competes with former Amazon chief executive Jeff Bezoss space venture Blue Origin and billionaire Richard Bransons Virgin Galactic in the burgeoning constellation of commercial rocket ventures.
All three rocket companies have successfully launched civilians into space.
According to Morgan Stanley, the space economy could be worth $1tn by 2040.
Musk, who also leads several futuristic companies including Tesla, Neuralink and Boring Company, said earlier this year that SpaceX will be landing its Starship rockets on Mars well before 2030.