In Denver, where nearly 27,000 rental units are vacant amid a housing crisis, housing advocates propose a "ghost tax" to incentivize landlords to make these units available and fund affordable housing initiatives. The tax aims to combat the imbalance between empty homes and people in need of housing, but landlords fear it may drive rents up further in an already expensive market. As Colorado grapples with housing affordability issues, advocates believe taxing vacant units could be a crucial solution.