Amazon CEO Jeff Bezos sold 531,852 shares, or about 1% of his total stake, for $990 million, says Business Insider. Bezos also donated another 268 shares — worth nearly $500,000 — to an unnamed nonprofit organization. Earlier that same week, Bezos sold 965,612 shares, garnering more than $1.8 billion. It's unclear why Bezos is selling stock and Amazon has declined to comment. Investors usually consider sales by a CEO or other top executives at company to be a bad sign.