Done-for-you 1120 filing

I conducted targeted searches of federal and state guidance and tax-practitioner resources to collect authoritative, up-to-date information (through Jan 2026) needed to create comprehensive blog and newsletter content about a "done-for-you" Form 1120 filing service for US businesses.

I retrieved federal instructions for Form 1120, IRS policy on mandatory e-filing and waivers, filing deadlines and extensions, penalty and interest rules, practitioner guidance on common mistakes and schedules, and state-level summaries and official Department of Revenue resources (California, New York, Texas) plus national state-tax overviews and practitioner guidance to support state-specific compliance considerations.

Summary of key findings and relevance for a done-for-you 1120 filing service 1) Federal filing basics and who must file - Form 1120 is the U.S. Corporation Income Tax Return used by domestic C corporations and entities (including LLCs) that elect corporate taxation.

It reports income, deductions, credits and determines federal corporate income tax liability. (See IRS Form 1120 pages.) 2) Deadlines, extensions, and estimated payments - Due date: Form 1120 is due the 15th day of the 4th month after the corporation’s tax year ends (calendar-year corporations typically due April 15).

Fiscal-year corporations follow the 15th day of the 4th month after year-end. - Extensions: File Form 7004 to request an automatic six-month extension to file (note: extension extends filing time only, not the time to pay taxes due). - Estimated tax payments: Corporations generally must make periodic estimated tax payments; failure to pay can result in penalties and interest. 3) Electronic filing requirements and options - IRS allows and encourages e-filing of Form 1120 and associated forms; for returns filed on or after Jan 1, 2024, corporations that file 10 or more returns of any type during the calendar year are required to e-file Form 1120 (reg. 301.6011-5).

Waivers are available for hardship. E-file supports electronic funds withdrawal for payments. - Approved commercial e-file providers and tax software (e.g., TaxAct, TurboTax business/E-file providers, commercial EDI/XML channels) are commonly used.

A done-for-you service must verify provider credentials, e-file approval status, and follow IRS e-file transmission rules. 4) Penalties, interest, and common errors - Late filing penalty: generally 5% of unpaid tax per month (up to 25%).

Late payment penalty: generally 0.5% per month on unpaid tax. Interest accrues on unpaid tax in addition to penalties. - Common errors: incorrect entity classification (filing wrong form), missing required schedules (e.g., Schedule UTP for large filers), misreporting income or credits, incorrect apportionment for multi-state activity, missing information returns (e.g., Form 5472 for certain foreign-owned corporations). - Amended returns use Form 1120-X. 5) State-level variations and practical compliance points for a done-for-you service - State corporate income/franchise taxes differ widely: some states impose corporate income tax (rates vary), some impose a franchise/privilege tax (e.g., Texas franchise tax), and apportionment formulas (single-sales, three-factor, double-weighted sales) and combined reporting rules vary by state. - Examples: Texas uses a franchise (margin) tax with an annual report due May 15 and specific rate/threshold rules (no corporate income tax); California’s Franchise Tax Board handles corporate franchise/income taxes and has state-specific filing forms and minimum taxes; New York Department of Taxation & Finance provides corporate tax forms and guidance including combined reporting where applicable.

A done-for-you service must: determine state nexus, identify required state returns, compute apportionment according to each state’s sourcing rules, check for combined/unitary reporting obligations, apply minimum taxes, prepare state-specific schedules, and e-file or transmit per each state’s filing system. 6) Best practices for building a done-for-you 1120 filing service - Documentation checklist: financial statements, year-end trial balance, depreciation schedules, payroll reports, Form(s) 1099 copies, prior-year returns (federal & state), estimated tax payment records, entity formation documents, ownership details (to identify foreign ownership requirements), intercompany agreements (for combined reporting review). - Client authorization and POA: get signed engagement letter and Form 8821 or Form 2848 if representation/third-party access to IRS is needed; secure permission for e-file signature, EFT payments, and direct communication. - Security & data handling: follow strong data-protection practices (encrypted transmission, secure client portals, least-privilege access), consistent retention policies, and clear privacy notices. - Deliverables & communication: draft return review, final signed forms, e-file/transmission confirmation, copy of filed returns and schedules, state filings, payment receipts, explanation of tax due/refund, and post-filing support including audit assistance options. - Pricing & service models: flat-fee packages (simple vs. complex returns), add-ons (state filings, amended returns, audit defense), subscription/retainer models for ongoing compliance and advisory services. 7) Recent compliance changes to note (through Jan 2026) - IRS e-file mandates (2024 rule re: mandatory e-file for filers with 10+ returns) and continued expansion of e-file and electronic notices. - State-level updates: states periodically change apportionment formulas, rates, combined reporting rules and minimum taxes; done-for-you services must monitor state DOF/FTB/comptroller bulletins.

Sources and verbatim excerpts supporting the above findings are listed next.

I conducted targeted searches of federal and state guidance and tax-practitioner resources to collect authoritative, up-to-date information (through Jan 2026) needed to create comprehensive blog and newsletter content about a "done-for-you" Form 1120 filing service for US businesses.

I retrieved federal instructions for Form 1120, IRS policy on mandatory e-filing and waivers, filing deadlines and extensions, penalty and interest rules, practitioner guidance on common mistakes and schedules, and state-level summaries and official Department of Revenue resources (California, New York, Texas) plus national state-tax overviews and practitioner guidance to support state-specific compliance considerations.

Summary of key findings and relevance for a done-for-you 1120 filing service 1) Federal filing basics and who must file - Form 1120 is the U.S. Corporation Income Tax Return used by domestic C corporations and entities (including LLCs) that elect corporate taxation.

It reports income, deductions, credits and determines federal corporate income tax liability. (See IRS Form 1120 pages.) 2) Deadlines, extensions, and estimated payments - Due date: Form 1120 is due the 15th day of the 4th month after the corporation’s tax year ends (calendar-year corporations typically due April 15).

Fiscal-year corporations follow the 15th day of the 4th month after year-end. - Extensions: File Form 7004 to request an automatic six-month extension to file (note: extension extends filing time only, not the time to pay taxes due).

3) Electronic filing requirements and options - IRS allows and encourages e-filing of Form 1120 and associated forms; for returns filed on or after Jan 1, 2024, corporations that file 10 or more returns of any type during the calendar year are required to e-file Form 1120 (reg. 301.6011-5).

Waivers are available for hardship. E-file supports electronic funds withdrawal for payments.

4) Penalties, interest, and common errors - Late filing penalty: generally 5% of unpaid tax per month (up to 25%). Late payment penalty: generally 0.5% per month on unpaid tax.

Interest accrues on unpaid tax in addition to penalties. - Common errors: incorrect entity classification (filing wrong form), missing required schedules (e.g., Schedule UTP for large filers), misreporting income or credits, incorrect apportionment for multi-state activity, missing information returns (e.g., Form 5472 for certain foreign-owned corporations). - Amended returns use Form 1120-X. 5) State-level variations and practical compliance points for a done-for-you service

- Examples: Texas uses a franchise (margin) tax with an annual report due May 15 and specific rate/threshold rules (no corporate income tax); California’s Franchise Tax Board handles corporate franchise/income taxes and has state-specific filing forms and minimum taxes; New York Department of Taxation & Finance provides corporate tax forms and guidance including combined reporting where applicable.

A done-for-you service must: determine state nexus, identify required state returns, compute apportionment according to each state’s sourcing rules, check for combined/unitary reporting obligations, apply minimum taxes, prepare state-specific schedules, and e-file or transmit per each state’s filing system. 6) Best practices for building a done-for-you 1120 filing service - Documentation checklist: financial statements, year-end trial balance, depreciation schedules, payroll reports, Form(s) 1099 copies, prior-year returns (federal & state), estimated tax payment records, entity formation documents, ownership details (to identify foreign ownership requirements), intercompany agreements (for combined reporting review). - Client authorization and POA: get signed engagement letter and Form 8821 or Form 2848 if representation/third-party access to IRS is needed; secure permission for e-file signature, EFT payments, and direct communication.

7) Recent compliance changes to note (through Jan 2026) - IRS e-file mandates (2024 rule re: mandatory e-file for filers with 10+ returns) and continued expansion of e-file and electronic notices.

• Estimated tax payments: Corporations generally must make periodic estimated tax payments; failure to pay can result in penalties and interest.
• Approved commercial e-file providers and tax software (e.g., TaxAct, TurboTax business/E-file providers, commercial EDI/XML channels) are commonly used. A done-for-you service must verify provider credentials, e-file approval status, and follow IRS e-file transmission rules.
• State corporate income/franchise taxes differ widely: some states impose corporate income tax (rates vary), some impose a franchise/privilege tax (e.g., Texas franchise tax), and apportionment formulas (single-sales, three-factor, double-weighted sales) and combined reporting rules vary by state.
• Security & data handling: follow strong data-protection practices (encrypted transmission, secure client portals, least-privilege access), consistent retention policies, and clear privacy notices.
• Deliverables & communication: draft return review, final signed forms, e-file/transmission confirmation, copy of filed returns and schedules, state filings, payment receipts, explanation of tax due/refund, and post-filing support including audit assistance options.
• Pricing & service models: flat-fee packages (simple vs. complex returns), add-ons (state filings, amended returns, audit defense), subscription/retainer models for ongoing compliance and advisory services.
• State-level updates: states periodically change apportionment formulas, rates, combined reporting rules and minimum taxes; done-for-you services must monitor state DOF/FTB/comptroller bulletins. Sources and verbatim excerpts supporting the above findings are listed next.