SpaceX (SPCX) IPO is significantly overvalued at $135, implying a ~$1.77T market cap versus a probability-weighted fair value of $91. Starlink is the core value driver, delivering $7.2B segment EBITDA in 2025 with a wide-moat, quasi-monopoly position and strong growth. xAI is a major risk, burning ~$1B/month and generating low-quality revenue, with governance and capital allocation concerns for outside shareholders.