Elon Musk's financial ecosystem is intricately detailed in SpaceX's recent S-1 filing, revealing over $660 million in transactions with his other companies, including Tesla, The Boring Company, and xAI. The filing highlights that SpaceX paid Tesla $144 million last year for various agreements, a notable increase from previous years. Additionally, xAI, which merged with SpaceX, spent $506 million on Tesla products, further illustrating the financial interdependencies among Musk's ventures. SpaceX's purchases included $131 million worth of Tesla Cybertrucks, potentially amounting to around 1,871 vehicles based on their retail price. The filing also notes that Tesla holds nearly 19 million shares of SpaceX, valued at approximately $4.1 billion based on a projected valuation of $1.5 trillion. As both companies work on collaborative projects like Macrohard, an AI platform, and Terafab, a chip manufacturing initiative, they aim to strengthen their partnership and explore future strategic collaborations.