Harvard needs 8% return every year just to keep the lights on. 5% spending plus 3% inflation. Miss that number and buildings stop, professors leave, research dies. 40% of the operating budget comes from one portfolio. Not tuition. Not grants. One fund. Jake Xia manages that fund's public markets. He also teaches the math behind it at MIT for free. One of the top five most-watched courses on OpenCourseWare. Millions of views. Almost nobody changed how they invest. Every year he hands students a blank page. Build a portfolio. No rules. Someone writes 100% Apple. Someone writes rare coins. Confident picks. Same blind spot, every time. Not one student asks the only question that matters: how much goes in each position. They all pick what to buy. Nobody sizes it. Sizing is the entire job. The answer won the Nobel Prize. It's called the efficient frontier. Xia draws it on the board in under a minute. Five equations sit underneath it. Compound growth. Present value. The geometric mean. The Rule of 72. Real return. All older than any bank on earth. All fit on a napkin. None behind a paywall. A "guaranteed 5% bond" during 4% inflation is a 1% return. The industry doesn't hide this. It just hopes you never run the equation yourself. The lecture is free. The napkin is free. The only thing that costs anything is not knowing.