On July 14, Arvind Krishna did something CEOs spend their entire tenure hoping to avoid. Eight days before IBM was scheduled to report second-quarter earnings, he published an open letter to investors warning that the results would fall well short of expectations. By the closing bell, IBM’s stock had fallen roughly 25%—the worst single day in the company’s 115-year history. Within days, Wall Street was debating whether activist investors might try to break up Big Blue.
