A multiphysics simulation is a computer model that links two or more interacting physical effects—such as heat, fluid flow, structural stress or electrical behavior—so they can be studied together instead of separately. For investors, it matters because these coupled models help companies predict real-world performance, cut costly prototypes, speed product development, and reduce technical risk before production or regulatory review; think of it like testing how a building handles wind, rain and weight simultaneously rather than one at a time.