It's possible that your marginal tax rate is a bit higher than your tax-bracket rate, although perhaps unlikely if you are in the 32% tax bracket. For example, it's possible that the additional $117 could make an additional $117 of investment income subject to Net Investment Income Tax of 3.8% (although it's possible that all of your investment income is already subject to that tax at an income level that puts you in the 32% tax bracket). You don't know your marginal tax rate for certain until you add the income as see hos it actually affects your tax liability. Marginal tax rate is:
(change in tax liability) / (change in taxable income)
