Investment interest is complicated.
First, you must report it in the year you paid the interest. So if you didn't pay in 2019, you have nothing to deduct.
Then, you can only deduct interest up to the amount of investment income. For example, if you borrowed $10,000 to buy stocks, and paid $500 interest but only received $200 of dividends, you can only deduct $200. The remaining interest can be carried forward until you have taxable income to declare. The carry over is tracked on form 4952.
Lastly, investment interest is an itemized deduction on schedule A, so even if you have deductible interest, you might not get an actual tax benefit unless your other itemized deductions are already larger than your standard deduction.
Other investment expenses, such as account maintenance fees and research, are not deductible for tax years 2018-2025 following the 2018 tax reform law.
