The Child Tax Credit may be limited, reduced, or excluded entirely due to the phaseout. What is the reduction of the Child Tax Credit for taxpayers with modified adjusted gross income over the threshold? $25 for each $1,000 (or fraction thereof) over the threshold. $50 for each $1,000 (or fraction thereof) over the threshold. $75 for each $1,000 (or fraction thereof) over the threshold. $100 for each $1,000 (or fraction thereof) over the threshold