Most federal subsidies aimed at helping households accumulate financial and tangible assets are delivered through tax expenditures—spending through the tax code. In 2013, these deductions, deferrals, and credits aimed at encouraging such asset building totaled over $350 billion, most devoted to homeownership and retirement saving incentives. Yet, these tax incentives do a remarkably poor job. In contrast to government appropriations, which at least sometimes are scrutinized though the congressional budget process and are currently limited by statutory caps, many tax expenditures grow automatically and are subject to little oversight. The mortgage interest deduction, for example, has been part of the income tax since its beginning in 1913. Even though there is much evidence that it is an inefficient tool to encourage home ownership,  American taxpayers  annually spend roughly $70 billion on the mortgage interest deduction—about the amount expected to be spent on food stamps. But while policymakers have just concluded an intense debate over whether to cut food stamps, few ask whether the mortgage interest deduction and other tax expenditures that support asset development achieve this goal. In a new paper, my colleagues Gene Steuerle, Signe-Mary McKernan, Caleb Quakenbush, Caroline Ratcliffe, and I reviewed the academic evidence and found that many of these tax expenditures fail to promote asset development. The mortgage interest deduction is not alone.  For instance, retirement saving subsidies do little to increase total overall wealth of lower-income households. Tax subsidies for activities such as home ownership and retirement savings benefit those at the top of the income distribution more than those at the bottom. Most come in the form of current deductions from income or as deferral of taxable income, which are typically worth more to taxpayers with higher marginal tax rates and can be worth little or nothing to taxpayers in the lowest tax brackets. For instance, about 70 percent of the tax savings from the mortgage interest and property tax deductions accrue to the households in the top 20 percent of income. Just 8 percent goes to middle-income households, and almost nothing to the bottom 40 percent. Similarly, roughly 70 percent of the tax subsidies for employer-based retirement savings and 65 percent of IRAs benefit the highest-income 20 percent of households. Although education subsidies are more progressive, the size of these tax expenditures is dwarfed by those for housing and retirement. The evidence from years of research is pretty clear: Current tax subsidies for asset building are poorly designed. They fail to increase savings much and overwhelmingly benefit the highest-income taxpayers who are least likely to need these incentives. When it comes to tax reform, they are low-hanging fruit.