Smart beta is one subset of factor investing. Factor investing harnesses the power of broad and persistent drivers of return. Factor investing can refer to macro factors (which affect returns across asset classes) as well as style factors (which affect returns within asset classes) and can be implemented with or without leverage. Smart beta strategies generally refer to style factors within a single asset class, implemented without leverage, most commonly in style factor strategies that are long only and index based, most commonly in an ETF.