Taxes are often the single largest cost faced by investors and have an outsized impact on after-tax wealth accumulation. A disturbing observation, however, is that much of the money held by taxable investors is managed as if it were untaxed. For taxable investors, the primary goal of investing is to maximize after-tax wealth. Investment managers who implement the key principles of tax efficiency, described below, will help their clients do just that. Although some of the examples are focused on index management, the same principles and techniques can be utilized across many different types of mandates such as factor-based strategies.