Expanded child tax credit may not be as generous as it seems

The expansion of a child tax credit helped seal Congress' approval of the Republican tax overhaul. Sen. Marco Rubio had insisted that House-Senate negotiators allow low-income households to claim more of the child credit. And the final bill did so.

So do poor families stand to benefit? Maybe. It depends on their circumstances.

The child credit is designed to help working families offset some of the cost of raising children. Under current law, the credit lets households reduce their taxes by up to $1,000 for each child under their care. The tax overhaul doubled that credit to $2,000.

It also made more of the credit refundable.