Elliott Investment Management, an activist investor, has built a nearly $2 billion stake in Southwest Airlines Co (NYSE:LUV), and is set to advocate for changes to enhance the airline’s underperforming shares. What Happened: Elliott Investment Management, a hedge fund led by billionaire Paul Singer, has amassed a stake of almost $2 billion in Southwest Airlines, reported The Wall Street Journal, citing people familiar with the matter. The firm intends to engage with Southwest’s management to address the airline’s underperformance. Southwest’s share price has plummeted by over 50% in the last t…