Sam Walton's autobiography mentions that his father-in-law provided the initial capital (that was about it), and his brother played an insignificant role (like buying things from suppliers). His brother, who was younger, was more of a helper while Walton built his first store (a Ben Franklin store that he later sold and started Walmart on his own based largely on his Ben Franklin stores).

Perhaps I'm quibbling, but an autobiography that downplays the contributions of others? Quel surprise!