Scene one: imagine a market where malicious actors deliberately cause a stock's price to fall through false negative statements.
Their goal is to buy back these shares at low prices, often before a positive announcement or a planned internal transaction.
Without the presumption of market fraud, each injured investor would have to prove individually that they were deceived, a Herculean task that would discourage most victims.
This presumption turns this individual challenge into a collective battle, facilitating legal recourse and making fraudsters accountable, similar to when companies manipulate their own shares before a buyout.