The rocket maker has been a useful financial tool for Mr. Musk, providing the billionaire with loans and aiding his struggling companies, a Times examination found.

Forbes has labelled Elon Musk 'among the least philanthropic billionaires', estimating that only a minute fraction of his $839 billion wealth has reached people in need.

In 2015, the Times says SpaceX started buying up Solar City’s debt at a time when he was that struggling company’s chairman. Eventually, after SpaceX had spent $255 million in this way, the Times says Tesla bought SolarCity for the equivalent of $2.6 billion. Musk says Tesla then repaid SpaceX for all that debt.