Child Tax Credit made fully refundable (no dollar cap or earnings limit on refundable portion). Maximum CTC increased to $3,000 for those children age 6 and older, increased to $3,600 for children under age 6. The increase in the maximum credit amount is phased out starting at $150,000 for married couples, $112,500 for heads of households, and $75,000 for others. CTC also expanded to include 17-year-olds.