Long before SpaceX was valued in the trillions and before Elon Musk became the world's richest person, one of his closest friends and earliest backers was spending nights on Tesla's factory floor helping solve production problems.That friend was Antonio Gracias, the founder and CEO of Chicago-based growth equity firm Valor Equity Partners. Known for his hands-on approach to investing, Gracias became one of Musk's most trusted allies over two decades, backing his companies during periods when many investors stayed away. Now, as SpaceX prepares for its hotly anticipated stock market debut, Musk might finally have found a way to say "gracias" to Gracias, as his loyalty could be rewarded with one of the largest-ever returns from a private investment.The SpaceX bet that could pay offThe biggest reward for that faith may now be just around the corner. The New York Times reports that Valor and Gracias-related entities control a stake in SpaceX valued at roughly $65 billion, based on the company's target IPO valuation of $1.77 trillion. The firm is currently the second-largest disclosed shareholder in SpaceX after Musk.The investment did not materialize overnight. Gracias first invested in SpaceX in 2008, when the company was still trying to prove that a privately run rocket business could succeed. He continued adding to that position over the years while also serving on the company's board.If the highly anticipated public offering performs as expected, the payoff could be historic. According to calculations from the publication, the SpaceX listing is expected to generate “one of the largest-ever returns from a private investment,” potentially making the 55-year-old investor one of the wealthiest people in the world.A friendship built before the billionsGracias and Musk first connected through PayPal circles in the early 2000s and quickly formed a relationship that extended well beyond business. Valor later became one of Tesla's earliest institutional investors in 2005, and Gracias would go on to join the boards of both Tesla and SpaceX.His commitment to Musk's ventures was not limited to board meetings and funding rounds. As Forbes notes, Gracias built a reputation for operationally involved investing, even sleeping on Tesla's factory floor to help work through manufacturing and supply-chain challenges during the company's most difficult periods.The partnership was tested during the 2008 financial crisis, when both Tesla and SpaceX were fighting for survival. Musk has previously revealed that Gracias stepped in with a $1 million short-term loan, helping him navigate one of the toughest chapters of his entrepreneurial career.Their friendship has remained strong ever since. In a recent post on X, Musk reflected on Gracias's long-standing support. "Antonio's ownership stems from absolute support, even when it looked like SpaceX would fail, and many investments over 2 decades. One could not ask for a better friend."— SMB_Attorney (@SMB_Attorney) Who is Antonio Gracias?Antonio Gracias is the founder and CEO of Valor Equity Partners, a Chicago-based growth equity firm with approximately $16 billion in gross assets, estimated Forbes.His entrepreneurial journey began in 1995 while he was studying law at the University of Chicago, where he founded the predecessor to Valor, MG Capital. After meeting Musk around 2000 through a mutual friend, Gracias became one of the billionaire entrepreneur's earliest and most consistent financial supporters.Much of his personal wealth already comes from his stake in Tesla, where he served as a director from 2007 to 2021. He also played a role in financing Musk's 2022 acquisition of Twitter and later assisted with restructuring efforts at the social media platform.