Millions of American families have few, if any, financial assets. The financial insecurity of households of color is even more severe: two out of three such households do not have enough savings to cover even a short-term disruption to their income. With more than half a trillion dollars in tax subsidies designed to encourage households to build wealth each year, it is important for advocates to understand what they are, how they work, and who benefits from them. This primer focuses on answering those questions and identifies ways that tax expenditures can be changed so that all households benefit.