According to the CBO, the bill would directly increase deficits by $1.4 trillion over the next decade, which is in line with what Republicans have said, but the resulting increase in interest payments on the debt would boost the total to $1.7 trillion.
The estimates do not take into account the offsetting revenue that could be raised if the bill passed as a result of stronger economic growth.
The deficit effects of the bill are an important factor for passing a permanent tax reform bill through the Senate reconciliation process with a simple majority. Also, several senators have indicated that they would not feel comfortable voting for a bill that added to deficits. Senate Republicans have not yet unveiled their own tax bill.