I'll assume you're being serious: 1 - Because Harvard invests in lots of things that aren't liquid and well-traded. It's hard to guess the next direction of t

I'll assume you're being serious: 1 - Because Harvard invests in lots of things that aren't liquid and well-traded. It's hard to guess the next direction of the U.S. stock market in part because the market is very liquid and there is a lot of volume. But Harvard also invests in things like timber lands (low deal flow), private equity (low liquidity), and other things that are very hard to price. These investments aren't available to you and I unless you happen to have $50 million laying around. 2 - Because when you have $40 billion to invest, very small differences in return make a massive different in dollars. If you're investing $40,000 then the last few pennies don't matter; if you're investing $40 billion those "pennies" are scholarships for 10 more kids. 3 - Because, as the the article implies, financial planning gets a lot more complicated when you have a different time horizon than "sometime in the future." A school like Harvard has spending needs every year and can't ride out a downturn the same way that a young kid saving for retirement can. On the other side, Harvard also hopes to last forever, and can make investments that won't pay off for 50 years. Time planning gets a lot more complicated. 4 - Taxes.