Complex sentence: Bush, while a corporate officer, sold stock in Harken soon before the company announced substantial losses, a transaction that resulted in a U.S. Securities and Exchange Commission investigation of probable insider trading; see George W. Bush's business and early political career.
Split into simpler sentences: Bush, while a corporate officer, sold stock in Harken shortly before the company announced substantial losses. This transaction resulted in a U.S. Securities and Exchange Commission investigation of probable insider trading; see George W. Bush's business and early political career.