There is no company that specifically benefits from a world war 3. However, some companies may benefit from certain aspects of a war, such as a surge in military spending or increased demand for certain materials. This can lead to an increase in the stock price of a publicly traded company listed on a stock exchange. Examples of companies that may benefit from increased military spending include arms and ammunition manufacturers, aerospace and defense contractors, and military technology companies. Additionally, companies that provide essential materials or services such as oil and gas, mining, and logistics may benefit from increased demand.