A sole proprietorship is an unincorporated business owned by an individual. The owner or taxpayer is responsible for such federal filings as income tax, self-employment tax, estimated taxes (paid monthly or quarterly), Social Security and Medicare taxes, income withholding taxes, information on Social Security, Medicare, and income tax withholding, FUTA (Federal Unemployment Tax Act) tax, and the the filing of information returns for payments to non-employees and transactions with other persons, and any excise taxes.