A socially efficient market outcome occurs when resources are allocated in a way that maximizes total societal welfare, meaning that the marginal social benefits of a good or service equal its marginal social costs. This concept emphasizes that not only should individual preferences be satisfied, but overall societal well-being should also be prioritized, leading to optimal production and consumption levels. In this context, it is essential to understand the balance between private incentives and social costs, which is fundamental to achieving efficiency in markets.