Ad fraud and non-viewable ads are problems for the digital ad industry, resulting in wasted time, effort, and money. This forecast report quantifies these problems and shows how we expect them to evolve over the next five years. We estimate the digital ad dollars lost on US desktop/laptop ads, segmented by display and video formats and by direct and programmatic inventory types. Both ad buyers and sellers should read this report to better understand the risks of ad fraud and non-viewability and how mitigating them can generate value.