Essential Tax Forms & Deadlines Guide for U.S. Businesses

C Corporation:

• Form: Form 1120
• Purpose: To report income, deductions, credits, and compute income tax liability.
• Taxability: Tax is levied at the entity level with shareholders paying taxes upon dividend distribution.
• Due date: Generally, the 15th day of the fourth month following the tax year’s end (April 15^th for calendar year corporations).
• Penalties: Penalties may be imposed for late filing or underpayment of taxes.

S Corporation:

• Form: Form 1120S
• Purpose: To report income, deductions, credits, and convey pass through information to shareholders.
• Taxability: No tax at entity level; tax is payable by shareholders.
• Due date: Usually, the 15^th day of the third month after the tax year concludes (March 15^th for calendar year S corporations).
• Penalties: Late filing or underpayment of taxes may incur penalties.

Sole Proprietor:

• Form: Form 1040, Schedule C
• Purpose: To report business income and expenses as part of the individual income tax return.
• Due date: Aligned with the individual income tax return deadline, generally April 15^th.
• Penalties: Late filing or underpayment of taxes may result in penalties

Partnership:

• Form: Form 1065
• Purpose: To report income, deductions, credits, and furnish details about business operations.
• Taxability: No tax at the entity level; partners are liable for taxes.
• Due date: Typically, the 15^th day of the third month following the tax year’s closure (March 15^th for calendar year partnerships).
• Penalties: Penalties may apply for late filing or underpayment of taxes.

Tax-exempt Organization:

• Forms: Vary based on size and activities (e.g., Form 990-N, Form 990-EZ, Form 990).
• Purpose: To report financial information and activities of tax-exempt organizations.
• Due date: Varies; Form 990 is typically due on the 15^th day of the fifth month after the fiscal year concludes.
• Penalties: Late filing penalties may be incurred, contingent upon gross receipts.