Kiddie Tax: 8615 - Is there a simplified way to fill this out so that it will assume the parents are in the top brackets, without knowing exact amounts?

[ad95PqrQ]

The kids have dividend income over $10k, and parents don't get around to filing taxes till October.  It would be nice for the kids to be able to submit their taxes well before then - if the parents are well into all the top tax brackets, the exact details aren't going to matter anyway, right?

[Hal_Al]

No. But, you can use estimates for the parent's income. After the parents actually file, you will only have to file amended returns for the kids if their bottom line changes

[ad95PqrQ]

But surely the max dividend tax rate stays the max?  If the kids report some very large number for parents income, why would the bottom line end up changing?  Does AMT status of the parent come into play?  (Parent dividend income exceeds $250k and involves an expensive accountant.  The idea here is to simplify the children's returns, not to attain an irrelevant degree of accuracy.)

[Hal_Al]

Dividends are investment income and subject to the "Net Investment tax", so there is a threshold at which the tax on dividends changes. But that's academic. Form 8615 is required and the parents income on line 6 is required.
 It's highly unlikely that the bottom line will change. That's why it's OK to use estimates of the parent's income. I wouldn't even bother to double check. If you're concerned, then file an extension  for the kids too and file their returns in Oct.
AMT does not come into play.

PS- I had to do form 8615, with capital gains, before there was tax software. I did invent a short cut. Today, TT does it for you and/or your accountant.