In 2016 taxes I had some investment expense deferred to 2017, since my investment income was less than the expense. Can I defer 2017 investment expense to 2018?

[CathiM]

Yes, your disallowed investment expense from 2016 will carry-forward to 2017 and if unused carry-forward 2018 as long as you file your tax return for 2017.  TurboTax will automatically carry that forward on Form 4952. 

"Form 4562 Part III serves two purposes—calculation any disallowed expense that you can carry forward to future years and determining your net investment interest expense deduction for the current year on line 8. This final amount is what you transfer to line 14 of Schedule A to be used as an itemized deduction on your taxes." Ref., What is Form 4952: Investment Interest Expense Deduction

[tharuns]

Isn't investment expenses one of the itemizations being removed from 2018?

[CathiM]

Investments expenses have not been specifically removed according to anything I have read. In fact, in the past investment expenses are miscellaneous itemized deductions (subject to the 2% of AGI limitation) and have not been allowed for AMT.  Since AMT is repealed, that should actually help investors with significant investments expenses. The changes may not allow some people to itemize, thus not allowing them to use the investment expenses.