Kevin Costner doesn't owe Stephen Baldwin squat after Baldwin sued him for allegedly duping him into prematurely selling shares of a company that scored a $52 million contract after the BP oil spill.

Moments ago, the jury rejected claims that Costner deceived Baldwin into selling shares of his stock in a company that made a financial killing by selling oil cleanup equipment in the wake of the BP spill.

It didn't take long for the jury to decide -- a verdict was reached in less than 2 hours of deliberation.

Baldwin and another plaintiff had collectively sought $17 million in damages.

Baldwin had previously argued that he sold his shares for a measly $500k ... but he would have made MILLIONS if he would have held on until after the BP deal.