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IRS Form 1120 (C Corporation Tax)

IRS Classification Code: 1120

Regulatory Mandate Analysis

Official IRS U.S. Corporation Income Tax Return. Used by C corporations to report income, gains, losses, deductions, and credits, and to figure the income tax liability of the corporation. Covers all domestic corporations subject to federal corporate income tax.

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Execution Architecture Steps

IRS Form 1120 – C Corporation Tax Return Guide

Form 1120 is used by domestic C corporations to report income, gains, losses, deductions, and credits to calculate their federal income tax liability.

Filing Deadline

Due on the 15th day of the 4th month following the end of the corporation's tax year (April 15 for calendar-year corporations). Extensions are available using Form 7004.

Key Requirements
  • Complete Schedule C for dividends and special deductions.
  • Attach Schedule M-1 or M-3 to reconcile book income to tax income.
  • Include all required subsidiary and affiliated group schedules.

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