加权平均资本成本(WACC) 在金融活动中用来衡量一个公司的资本成本。 因为融资成本被看作是一个逻辑上的价格标签，它过去被很多公司用作一个融资项目的贴现率。

公司从外部获取资金的来源主要有两种：股权和债务。因此一个公司的资本结构主要包含三个成分: 优先股，普通股和负债（常见的有债券和期票）。加权平均资本成本考虑资本结构中每个成分的相对权重并体现出该公司的新资产的预期成本。

The weighted average cost of capital (WACC) is the rate that a company is expected to pay on average to all its security holders to finance its assets. The WACC is commonly referred to as the firm’s cost of capital. Importantly, it is dictated by the external market and not by management. The WACC represents the minimum return that a company must earn on an existing asset base to satisfy its creditors, owners, and other providers of capital, or they will invest elsewhere.