The Affordable Care Act (ACA), signed into law in 2010

The Affordable Care Act (ACA), signed into law in 2010, introduced several tax code changes that began taking effect in 2013. These provisions aimed to fund healthcare expansions, promote coverage, and address costs, primarily targeting higher-income individuals and certain industries while introducing new rules for deductions and reporting.The most prominent 2013 changes were two new taxes on higher earners, designed to help finance the ACA’s subsidies and coverage expansions:

1. Additional Medicare Tax (0.9%) — This surtax applies to wages, compensation, and self-employment income exceeding specific thresholds: $200,000 for single filers, $250,000 for married filing jointly, and $125,000 for married filing separately. It supplements the standard 1.45% Medicare payroll tax (with employers matching), making the total Medicare tax rate 2.35% on income above the threshold. Employers withhold the additional amount on wages exceeding the limit, but self-employed individuals calculate and pay it via their tax return.
2. Net Investment Income Tax (NIIT, 3.8%) — This tax targets certain unearned income for high earners, including interest, dividends, capital gains, rental and royalty income, non-qualified annuities, and income from passive activities or businesses. It applies when modified adjusted gross income (MAGI) exceeds $200,000 (single), $250,000 (joint), or $125,000 (married separate). The tax is the lesser of 3.8% of net investment income or the amount by which MAGI exceeds the threshold. It does not apply to wages, self-employment income (already subject to the additional Medicare tax), or distributions from qualified retirement plans.

Other notable 2013-related adjustments included:

• A raised threshold for itemizing medical expenses: The floor increased from 7.5% to 10% of adjusted gross income (AGI) for most taxpayers (though the 7.5% threshold continued for those 65+ through 2016). This made it harder to deduct unreimbursed medical costs.
• Employer reporting of health coverage value on Form W-2 (Box 12, Code DD) became required, though the amount remained non-taxable.

These 2013 provisions focused on revenue generation from affluent taxpayers and investment income to offset ACA costs, rather than the individual mandate penalty (which started in 2014) or premium tax credits (also 2014). Together, they represented key early tax code integrations of the ACA, affecting tax planning for higher-income households, investors, and those with significant medical expenses.