12% could be troublesome if it's mandatory
The big question is how to pay for all the tax cuts. The bill can only add $1.5 trillion to the deficit over 10 years.
How will the rest be paid for. A big way appears to be a 12% one-time tax on overseas assets of US corporations. First of all, that's higher than the 10% rate that was floated.
Secondly, the language isn't 100% clear but there is talk that it's mandatory so it would mean the tax applies whether or not the money is brought home. That would hurt companies with no intention of bringing the money to the US.
Apple, for instance, has something like $300 billion overseas so it would be hit with a $36 billion bill. Overall, there is something like $2 trillion overseas and that would be a $240 billion hit to corporates.