The following tax base calculation involves a five-year average of net capital. The Michigan franchise tax is based on a financial institution's total equity capital as calculated in accordance with generally accepted accounting principles.The capital stock is an important source of propagation in slumps, a point that has escaped analysis in the cycle-around-trend view of fluctuations. You may owe capital gains taxes if you sold stocks, real estate or other investments. Use SmartAsset's capital gains tax calculator to figure out what you owe. Report losses due to worthless securities on Schedule D of Form 1040 and fill out Part I or Part II of Form 8949. This booklet is intended as a guide to help complete the. Capital gains tax on investment income. If you invested in the stock market and made money, your profit may be classified as a capital gain. Or, enclose the check with the corporation's income tax return.