Koch, 79, died after years of fighting various illnesses. Through the David H. Koch Foundation, he pledged or contributed more than $1 billion to philanthropic causes.
Financier and convicted pedophile Jeffrey Epstein was in jail awaiting trial on charges of conspiracy and trafficking minors for sex when he hanged himself.
Direct investments are increasingly appealing to high-net-worth individuals looking to eliminate management fees and more closely align investments with their values.