Yes, depending on the circumstances. Most marketplace enrollees choose to have their subsidy sent directly to their health insurance company each month, although it's also possible to pay full price during the year and then claim the subsidy on your tax return. Assuming you take the subsidy upfront (paid to your insurer each month), you do have to reconcile it on your tax return. If your subsidy was too small, you can claim the rest on your tax return. But if your subsidy was too large (perhaps because your income ended up being more than you expected), you may have to repay some or all of the subsidy that was paid on your behalf.