Background reading: For technical background on U.S. business taxation (entities, deadlines, state rules), see our guide: U.S. Business Tax Guide.
Corporate & Business Tax Filing Service (Federal, State & Local)
We prepare and file complete business tax packages for C-corps, S-corps, partnerships/LLCs, and foreign-owned entities operating in the U.S. Our support spans entity set-up and registrations, return preparation and e-filing, multi-state (SALT) filings, sales & use tax, employment/payroll taxes, information reporting (e.g., 1099/1042-S), and notices/resolutions. If you prefer a single point of accountability for all deadlines and forms—we’ll run the entire calendar for you.
Who files what—and by when?
- C corporations file Form 1120 (federal) by the 15th day of the 4th month after year-end (calendar year: mid-April). Many states require separate corporate income/franchise returns. We can obtain a filing extension via Form 7004 (time to file, not to pay) and prepare estimated payments (e.g., 1120-W computations).
- S corporations file Form 1120-S by the 15th day of the 3rd month after year-end (calendar year: mid-March). Shareholders receive Schedule K-1 (and K-3 when international detail is required).
- Partnerships / multi-member LLCs file Form 1065 on the same schedule as S-corps. Partners receive Schedule K-1 (and K-3 if applicable).
- Foreign corporations with U.S. trade/business or ECI generally file Form 1120-F. We also handle protective returns to preserve deductions/refunds if needed.
- Foreign-owned U.S. disregarded entities (e.g., single-member LLCs) may need a pro-forma Form 1120 with Form 5472 when reportable related-party transactions exist. We prepare the package and required EIN/records.
We manage all federal/state extensions, estimates, and e-file authorizations—end-to-end.
State & Local (SALT) returns
States impose income/franchise or gross-receipts taxes, with separate nexus and apportionment rules. Several states offer or require pass-through entity (PTE) taxes. Cities and localities can impose business taxes too. We evaluate nexus (physical/economic), register where required, compute apportionment, and prepare each jurisdiction’s filings.
Sales & Use Tax
After economic nexus became common, remote sellers and marketplace participants often must collect and remit sales tax. We handle registrations, exemption certificates, matrixing of taxability, filing frequency setup (monthly/quarterly/annual), return preparation, and remittances. We can also clean up past exposure via voluntary disclosure programs where appropriate.
Employment (Payroll) Taxes
- Federal: Form 941 (quarterly), Form 940 (annual FUTA), W-2/W-3 year-end, and deposit schedules.
- State: employer withholding, unemployment insurance, and local payroll taxes where applicable.
We register new payroll accounts, coordinate with your payroll provider/PEO, monitor deposits, and prepare or review returns.
Information reporting & withholding
We prepare year-end information returns: 1099-NEC/MISC (U.S. payees) and 1042-S (foreign recipients) with corresponding annual transmittals (1096/1042, as applicable). We also design your W-9/W-8 intake and withholding controls to minimize penalties and notices.
Our preparation process
- Onboarding & calendar. We analyze your entity structure, states, and payment flows; then publish a compliance calendar with all deadlines.
- Data collection. We collect trial balance/books, bank/merchant summaries, payroll and sales data, and prior-year returns. For cross-border items, we map related-party transactions and documentation.
- Preparation & review. We prepare returns (federal, state, local), compute tax and estimates, and draft K-1/K-3, 1099/1042-S, sales tax, payroll, and any required information returns.
- E-file & payments. We obtain signatures (e.g., Form 8879/8453), e-file, schedule electronic payments, and deliver a year-end packet with next-year recommendations.
- Notices & amendments. We respond to tax notices, prepare amended returns, and handle voluntary disclosures or late filings if needed.
Prefer to focus on running the business? Hand us the compliance. We’ll keep you on time and in good standing—federally and across the states.
Corporate Tax Filing – Frequently Asked Questions
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C-corp: 1120. S-corp (with valid election): 1120-S. Partnership/multi-member LLC: 1065. Foreign corporation with U.S. trade/business: 1120-F. Foreign-owned U.S. disregarded entities may need a pro-forma 1120 with 5472.
1120 is due the 15th day of the 4th month after year-end; 1120-S/1065 are due the 15th day of the 3rd month. We file Form 7004 to extend the filing deadline (payments are still due by the original due date).
Yes. We assess nexus and apportionment, register in required states, and prepare state income/franchise, city, and local returns. We also advise on PTE elections and credits.
We evaluate physical nexus (property/people) and economic nexus (sales thresholds/marketplace activity), then map filing obligations and registration steps for each jurisdiction.
Absolutely. We register accounts, set filing frequencies, configure product taxability, prepare returns, and remit payments. We can also pursue voluntary disclosure for past liabilities where appropriate.
We set up federal/state payroll accounts, coordinate deposits, and prepare or review 941/940, W-2/W-3, and state unemployment/withholding returns. We work with your payroll provider/PEO or run the filings ourselves.
Yes. We manage W-9/W-8 intake, determine who gets 1099-NEC/MISC vs. 1042-S, and file annual transmittals (1096/1042/1042-T) as required.
Often yes if there are reportable related-party transactions. We’ll confirm applicability, obtain the EIN if needed, and file 5472 with the required pro-forma 1120 when triggered.
When it has effectively connected income (ECI) with a U.S. trade/business or seeks to preserve deductions/refunds via a protective filing. We assess the facts and prepare the return.
Yes. We produce owner packets with K-1 and, when applicable, K-3 for foreign tax credit and other international detail.
We compute safe-harbor estimates, generate vouchers, and schedule electronic payments (federal and state). We also forecast next year’s cash taxes.
Some states allow pass-through entities to pay state tax at the entity level, potentially benefiting owners (SALT cap workarounds). We model the election and handle filings if it’s beneficial.
Prior-year returns, a current trial balance, bank/merchant summaries, payroll and sales reports, cap tables/ownership, related-party agreements, and state/city account IDs. We’ll send a tailored checklist.
Yes. We file 7004 for federal (and state equivalents), compute an extension payment, and then finalize the returns during the extension period.
We review the notice, respond with substantiation, and, if needed, represent you in exam. Our workpapers are organized to support positions taken on the returns.
Yes. We connect to common payroll providers and accounting systems to automate data pulls and reduce manual effort.
We prepare delinquent and amended returns, pursue penalty relief when available, and coordinate any voluntary disclosure or payment plans.
Yes. We analyze cash vs. accrual, inventories, depreciation, and interest limitation methods; where beneficial, we file method changes and compute any §481(a) adjustments.
An authorized officer/partner signs (or e-signs) the return. We provide the appropriate e-file authorization forms (e.g., 8879 series/8453) for signature.
Fees depend on entities, states, and the filings needed (federal, SALT, sales tax, payroll, information returns). See our current tiers and examples on the pricing page.
Want one team to run your entire tax calendar—federal, state, sales tax, payroll, and year-end reporting? Contact us or review pricing.