Mark Cuban told "The David Rubenstein Show" about his buy-and-hold stock strategy. Business Insider reports the strategy led him to big returns on Netflix and Amazon. The "Shark Tank" investor owns the NBA's Dallas Mavericks said he stuck with companies he believed in. He owned Netflix stock since it cost $50 a share. The streaming service closed Wednesday near $550. He owned Amazon shares at just under $2,000. On Wednesday, Amazon closed at $3,441.85.