IRS Form 1120 (2015): U.S. Corporation Income Tax Return

Domestic C corporations file IRS Form 1120 (2015) to report income, losses, deductions, capital gains, and credits for the tax year. All domestic corporations must file it to determine their federal income tax liability unless exempt under Section 501 or required to file a special return.

Late Filers

Corporations that missed the March 15, 2016, deadline may still file Form 1120 for 2015 to stop additional failure-to-file penalties and maintain IRS compliance records.

Multiple Income Sources

C corporations must report all 2015 income sources, including operations, capital gains, dividends, and rentals, on correct Form 1120 lines following IRS reporting instructions.

Itemizing Deductions

Corporations must deduct compensation, depreciation, and interest on Form 1120 and keep records and report them accurately on the 2015 schedules.

Claiming 2015 Credits

Corporations eligible for 2015 tax credits, including general business and research credits, must compute amounts and attach required IRS forms when filing Form 1120 returns.

IRS Compliance

Domestic corporations generally must file Form 1120 for 2015 regardless of income. Failure-to-file penalties apply to unpaid taxes, but filing remains required for compliance purposes.

Citizens Abroad / Military

Domestic corporations with international operations must still file Form 1120 for 2015, reporting worldwide income and attaching required international schedules under applicable IRS filing rules.

Complete your 2015 Form 1120 correctly with these steps. Some steps follow the 2015 tax year rules that do not apply to later filings.

1. Gather Your Documents Before Starting

Before completing Form 1120, collect all financial records for 2015, including income statements, balance sheets, payroll records, depreciation schedules, and any prior-year IRS transcripts confirming your filing status and amounts already paid or assessed.

2. Choose the Correct Filing Status

Domestic C corporations are the sole entities that submit Form 1120. Instead, corporations that have elected S corporation status must use Form 1120-S. Please verify that your corporation did not make an S election before the 2015 tax year, as an incorrect form may be rejected or applied incorrectly.

3. Report All Income on the Correct Lines

Report gross receipts or sales on line 1a, dividends on line 4, interest on line 5, gross rents on line 6, and gross royalties on line 7. Capital gains from Schedule D are reported on Line 8. For 2015, all domestic and foreign income must be included in the corporation's total gross income.

4. Calculate Adjusted Gross Income (AGI)

Form 1120 calculates taxable income for corporations, not AGI for individuals. Subtracting officers' compensation, salaries and wages, repairs, bad debts, and depreciation from gross income yields taxable income before the net operating loss deduction and special deductions, which determine the tax rate.

5. Choose Your Deductions and Apply Exemptions

Corporations compute taxable income by subtracting allowable business deductions from gross income; no individual-style standard deduction applies on Form 1120. The dividends-received deduction, reported on Schedule C, reduces taxable income and varies based on ownership percentage in the dividend-paying corporation, affecting overall business income tax liability and calculated corporation taxable income.

6. Claim the 2015-Specific Credit

Corporations eligible for the 2015 general business credit must complete Form 3800 and attach it to Form 1120. The credit reduces tax liability and may be carried back one year or forward up to twenty years if unused.

Missing W-2s or Tax Records for 2015?

Late filers often lack original payroll records or income documents from 2015. The IRS and other resources maintain records that can help reconstruct the information needed to complete an accurate corporate return.

IRS Wage & Income Transcript

An IRS Wage and Income Transcript shows W-2s and 1099s reported to the IRS for individuals and is not typically used for corporate Form 1120 reconstruction purposes.

IRS Account Transcript

An IRS account transcript summarizes corporate tax-year activity, including filings, payments, penalties, credits, and IRS adjustments, helping businesses verify account status and reconcile prior Form 1120 reporting records.

Social Security Administration

The SSA may provide W-2 copies or earnings records to individuals or authorized representatives to serve personal wage verification needs rather than corporate Form 1120 reconstruction purposes.

Contact Prior Employers

Employers are generally required to retain payroll records for at least four years, though the availability of 2015 documentation depends on specific retention policies and whether requirements have expired.

Late filing incurs a 5% monthly penalty on unpaid tax, compared to a 0.5% failure-to-pay penalty, so timely filing reduces overall liability.

The errors below are the most frequent causes of IRS delays, rejected returns, and missed credits on 2015 Form 1120 filings.

• Using the wrong tax year form — The 2015 Form 1120 contains different schedules and line references; using another year’s version causes rejection, processing delays, or IRS account mismatches.
• Missing Schedule M / 2015-specific credit — Omitting required schedules like M-1 or M-3 for $10M+ asset corporations, or missing credit forms, triggers an IRS review and significantly delays processing.
• Wrong filing status label — Filing Form 1120 instead of 1120-S for S corporations or incorrect entity classification leads to invalid returns and may require amended filings.
• Applying Pease limitations incorrectly — Individual deduction phaseouts do not apply to corporations; misapplying them distorts taxable income calculations and results in incorrect corporate tax liability reporting.
• Treating unemployment compensation as partially tax-free — Misclassifying income items as partially exempt leads to underreporting, since corporate income must be fully reported under applicable federal tax rules.
• Assuming a refund is still available — Under IRC §6511, most 2015 refund claims are time-barred; eligibility depends on filing and payment dates, so assumptions often result in missed claims.
• Missing or incorrect Social Security numbers — Incorrect EINs or identifiers prevent IRS matching of returns to accounts, causing processing delays and potential misapplication of payments or penalties.
• Unsigned return — A Form 1120 without an authorized corporate officer’s signature is considered unfiled by the IRS and subject to full failure-to-file penalties.
• Missing attachments — Required schedules, credit forms, and supporting statements must be included; missing attachments trigger IRS correspondence and result in an incomplete return status.

What is IRS Form 1120 (2015) used for?

IRS Form 1120 for 2015 is the U.S. corporate income tax return used by domestic C corporations to report income, deductions, credits, gains, and losses, and to compute total federal income tax liability owed to the IRS for that tax year.

Can I still file a 2015 tax return?

Yes, Form 1120 for 2015 can still be filed late. Filing stops the failure-to-file penalty from increasing and creates an official IRS record. Refund eligibility depends on IRC §6511 time limits tied to filing and payment dates, which may have already expired.

Is there a penalty for filing Form 1120 late?

Yes, the IRS imposes a 5% monthly failure-to-file penalty on unpaid tax, plus a 0.5% failure-to-pay penalty. When both apply, the filing penalty is reduced. Minimum penalties apply to returns more than 60 days late, based on the tax due.

What if my corporation had no income in 2015?

Most domestic corporations still had to file Form 1120 for 2015, even if they had no income or taxable income, unless exempt. Zero-tax returns may avoid penalties tied to unpaid taxes, but filing remains required to maintain compliance with IRS rules.

Can I amend my 2015 Form 1120 if I made errors?

Correct a 2015 return by utilizing Form 1120-X, which includes supporting documents and explanations. the corporation's filing and payment history with the IRS, as well as the time limits outlined in IRC § 6511. Any refund or additional tax is contingent upon these factors.

Do I need to file a state return as well?

A corresponding state corporate tax return is also required for most corporations when they file or amend Form 1120. Check the revenue department guidelines for your state, or consult a qualified tax professional, to ensure compliance, as requirements may differ by state.

What records should I keep after filing?

Corporate records should be retained for three years, six years if underreporting exceeds 25%, four years for employment taxes, and longer for specific deductions or assets. Retention is contingent upon the IRS's limitation periods and the potential for audit or adjustment risk.