During her senior year as an economics major at Yale, Casey Whalen enrolled in a senior seminar, one of only about 15 students in the class. The instructor was David Swensen, author of the landmark book Pioneering Portfolio Management: An Unconventional Approach to Institutional Investment, which enumerated the principles that became known as both the “Yale model” and the “endowment model” of investing, a portfolio theory heavy on alternatives and illiquid assets. He used that investing philosophy to grow the Yale endowment from $1.3 billion when he became CIO in his early 30s, to more than $30 billion during his 35 years in the post, earning international renown along the way for his performance.