The amount of premium tax credit that you can claim is based on your household income and the members of your household. To obtain a premium tax credit, you must file a tax return with the IRS for 2014. You will also need to fill out an application on www.healthcare.gov and provide information about your household members and your estimated income for 2015. The federal Marketplace will then estimate the amount of premium tax credit that you can claim on your tax return. Once the amount of premium tax credit has been determined, you can choose to accept all, accept a portion, or deny the premium tax credit. If you did not have a marketplace plan, you need to apply on www.healthcare.gov during your special enrollment period (SEP).