So lets say someone makes $30k a year and has to buy their insurance on the exchange. Clearly, they're not paying much in Fed taxes after they send in their taxes for the year (or more likely, collect their tax return for the year). Can the subsidy that is their reduced tax burden actually see them getting a tax refund that puts them at more than $0? As in, they have paid negative taxes?
Chuck
It's a bit of a complicated answer and gets a bit esoteric and involved in parsing language, so forgive me if the explanation isn't the best. For the sake of simplicity, let's assume that you are single, no dependents, and make $5,000 (net of payroll tax but gross of income tax). You have no tax issues and can file an EZ form.
Your income, $5,000, goes on line 1. You have no taxable interest on line 2 or unemployment compensation on line 3. That means your Adjusted Gross Income on line 4 is $5,000. Nobody can claim you as a dependent so you enter your exemption of $10,000 on line 5. Your line 6 taxable income is $0.
Based on your taxable income and the tax table your tax liability for the year is $0.
Because your line 4 AGI is <$13,980 and your line 1 income is <$13,980 you qualify for the Earned Income Tax Credit in the amount of $384. Your net tax contribution is -$384, which you can have refunded to you.
However, when dealing with the Premium Tax Credit the net tax contribution cannot be refunded (to the extent it results from the Premium Tax Credit). For example, if you make 133% of the Federal Poverty Level ($15,282 for a single person) you can qualify for a tax credit that requires your annual premium to be no more than 2% of your income (~$305). Any cost in excess of that amount is paid by the government to the insurer on your behalf with no limit (subject to the provisions of 26 USC § 36B).
In a random county where I live, the annual premium for a person aged 64 on the second-lowest cost silver plan (the bellweather for the tax credit) is $13,393. That means my tax credit is $13,088 ($13,393 - $305). My tax liability for the year is $528 (based on taxable income of $5,282). My net tax contribution is -$12,520 ($528 - $13,088). The caveat is that I can only see that $13,088 tax credit if I buy the 2nd low silver plan. If I go cheap and buy the lowest bronze plan ($9,593 in that state/county) my tax credit is $9,288 ($9,593 - $305); the difference, $3,800, is lost to me.
I guess it's a way of saying that the "difference" in tax credits is lost (nonrefundable) if you elect to go with cheaper coverage.