As we explain below, there are three major reasons for the differences between our estimates and those of the Fox Study: First, the Fox Study substantially overstates un-collected taxes associated with business to- business (B2B) online sales; second, the Fox Study un-derstates tax collections by small firms; third, with respect to “out-year” projections, the Fox Study assumes what we regard as an unrealistically high and unsustainable growth rate for online sales, especially considering the fact that the growth of broadband penetration among U.S. households – one of the primary drivers of online sales growth – is slowing as household broadband penetration approaches saturation.