"Many people blamed Byrne’s obsessive and vindictive behavior for the fluctuations in his company’s stock price, but Byrne believed that the company was a victim of “naked short selling”—a largely illegal form of stock manipulation, not widely discussed at the time, in which a trader, selling short stock that he or she hasn’t actually borrowed, can potentially put overwhelming downward pressure on a company. The selling of such phantom shares was possible because of a three-day lag that was built into the process of settling trades. This weakness, Byrne believed, had the potential to destabilize the stock market, likely with disastrous consequences. https://outline.com/2YTZ38 Long article. Good introduction to a darker side of Wall Street