For tax year 2017, estates and trusts are subject to the net investment income tax if they have undistributed net investment income and AGI exceeding which threshold?

For tax year 2017, estates and trusts are subject to the net investment income tax if they have undistributed net investment income and adjusted gross income (AGI) exceeding the threshold of $12,500. This tax is designed to apply to certain investment income, including interest, dividends, and capital gains, and it kicks in for estates and trusts once their AGI surpasses this specific amount.

The amount of $12,500 represents the threshold established for tax purposes, indicating that estates and trusts under this AGI would not be liable for the net investment income tax. Understanding these thresholds is crucial for tax compliance and planning, especially in the management of estates and trusts, where investment income can significantly impact tax liabilities.