Literally translated from Latin: from before. The term describes activities (e.g. actions, decisions, formation of expectations) that are undertaken before the state of nature is revealed. For instance, a firm may make an ex ante plan to invest next year, but when next year arrives market conditions may be poor (the realized state of nature) and the firm may have no incentive to undertake the investment. Ex ante is contrasted with ex post, meaning as viewed after the event.