What is 3-6-3 Club?
A group of thrifters (money lenders) who are given loans at a fixed 3% rate, dole out loans with a 6% interest rate, and arrive for golf at three in the afternoon--hence 3-6-3.
First mentioned in Michael Lewis' Liar's Poker book, a typical 3-6-3er was a balding, middle-aged man who thought nothing only of money.
"Man, those guys from the 3-6-3 club are buying our junk bonds."
"Yeah, not too smart, eh?"