Which filing status would typically result in the highest tax liability?

Choosing the filing status of "Married Filing Separately" generally results in the highest tax liability. This is because tax brackets for this status are typically less favorable compared to those for "Married Filing Jointly" or "Head of Household." When filing separately, taxpayers lose out on several beneficial credits and deductions that are available to married couples filing jointly or qualifying individuals filing as heads of household.

For instance, certain tax credits, such as the Earned Income Tax Credit and the Child Tax Credit, are not available to those who file separately. Additionally, the phase-out thresholds for these credits might apply differently, leading to higher overall tax liabilities when separated.

Furthermore, certain deductions—like the maximum deduction for IRA contributions—are limited if one spouse files separately and the other has access to a workplace retirement plan. This can also increase taxable income, compounding the overall tax liability when filing separately.

In general, married couples often find more advantageous tax treatment by filing jointly, which typically results in lower combined effective tax rates. Therefore, "Married Filing Separately" is usually the least favorable filing choice for tax liability, leading to the conclusion that it results in the highest tax burden among the listed filing statuses.