Most Americans think government spending is only what appears on the federal budget table. But there is a parallel ledger called tax expenditures — revenue foregone through deductions, credits, and exclusions that often exceed direct appropriations. In this episode, Lucas and Luna drill into the mortgage interest deduction, a policy that costs roughly one hundred billion dollars annually yet benefits higher-income households disproportionately. They explore how these hidden subsidies reshape housing markets, distort investment decisions, and create a complex web of public finance that traditional budget analysis often misses. The conversation examines why reforming tax expenditures is politically difficult despite their massive fiscal impact.