Shares of Southwest Airlines rose 9% on Monday and headed toward their largest single-day gain in nearly four years, after activist firm Elliott Investment Management announced a nearly $2 billion stake in the company and called to oust the airline's chief executive and board chair. Southwest shares rose to$30.25 Monday morning, on track for the company's largest single-day jump since November 2020. Savanthi Syth, an analyst for the investment bank Raymond James, said it is "unclear if a management change ...