Detail the specific rules around the deductibility of investment interest expenses, including the limitations and how these deductions are calculated.

Investment interest expense is the interest you pay on money borrowed to buy investments. It’s a deduction that can reduce your taxable income, but its deductibility is subject to specific rules and limitations. It's important to understand these rules to correctly calculate and claim this deduction on your tax return. The deduction is designed to apply to interest incurred on money borrowed for investments, not for other personal or business use. The primary rule for deducting investment interest expense is that it's limited to the amount of your net investment income for the year. This means you can't deduct more investment interest expense than the income generated from your investments. Net investment income is your gross investment income minus your investment expenses, but these expenses do not include interest expense. Investment income includes dividends, interest, capital gains, and income from royalties, but excludes any income earned from operating a business or from the performance of services. Examples of investment expenses include brokerage fees, investment advisory fees, and other expenses directly related to managing your investments but not the cost of purchasing the investment itself. For instance, let’s say that during the year, you receive $10,000 in dividend income, $5,000 in interest income, and $3,000 in capital gains, for a total investment income of $18,000. You also incurred $2,000 in investment expenses, but not any interest exp....