Get your taxes done using TurboTax

had you made the proper election each year, you could have added taxes and any interest paid that year to the tax basis. Otherwise, they and the other costs might have been deductible as investment expenses until the TCJA became tax law. it bars the deduction for investment expenses and is in effect through at least the end of 2025 (no one knows if it or parts will be extended).   so if you sell only the closing costs (buy and sell) would add to the tax basis.