Business Tax Filing for U.S. Corporations, S Corps and LLCs
Make Corporate Tax Filing Easy with Expert U.S. Support
Federal Tax Returns (Form 1120 / 1120-S / 1065)
State & Local Filings (All 50 States)
Strategic Tax Planning
IRS Compliance & Notice Support
Sales Tax & Nexus Analysis
Fast Electronic Filing
U.S. Business Tax Deadlines at a Glance
Calendar-year filers work to four dates. Miss one and the penalty is charged per owner, per month, which is why late filing costs partnerships and S corporations the most.
March 15
S corporations (Form 1120-S) and partnerships (Form 1065). Schedule K-1 goes to every owner on this date.
April 15
C corporations (Form 1120) and individual returns (Form 1040). First quarter estimated payment is due the same day.
September 15
Extended Form 1120-S and Form 1065 returns. This is the next deadline for businesses that extended.
October 15
Extended Form 1120 and Form 1040 returns. Extensions move the filing date, not the payment date.
Dates apply to calendar-year filers. If a deadline falls on a weekend or a federal holiday it moves to the next business day, and state deadlines can differ from the federal date.
Our Corporate Tax Filing Methodology
A systematic and precise process designed to ensure accurate filings and maximum tax efficiency for your business.
All-Inclusive Tax Filing Services for Maximum Accuracy
Stress-free U.S. tax filing. Choose Orbit Accountants and put hectic business tax seasons behind you.
All-Inclusive Tax Filing Services for Maximum Accuracy
Stress-free U.S. tax filing. Choose Orbit Accountants and put hectic business tax seasons behind you.
Modern Systems for Accurate Tax Filing
We use clean bookkeeping, payroll records, and tax-ready workpapers to prepare accurate business filings, identify deductions, and keep your business aligned with IRS and state requirements.
Data
Records
Review
Review
Simplify Corporate Tax Filing with Orbit
A streamlined, professional onboarding experience designed to get your finances back on track-fast and hassle-free.
The Problem
- Complex US tax regulations at federal, state, and local levels.
- Risk of IRS penalties from errors or missed filings.
- Time wasted deciphering ever-changing tax codes.
- Overlooked deductions and credits that could save money.
The Solution
- Accurate and timely preparation of Form 1120, 1120-S, and all required schedules.
- Strategic tax planning to minimize liability.
- Expert handling of IRS compliance and state tax requirements.
- Clear communication and proactive updates throughout the process.
The Outcome
- Stress-free tax compliance.
- Lower tax liabilities with smart strategies.
- More time to focus on your business.
- Peace of mind with expert support.
The Problem
- Complex US tax regulations at federal, state, and local levels.
- Risk of IRS penalties from errors or missed filings.
- Time wasted deciphering ever-changing tax codes.
- Overlooked deductions and credits that could save money.
The Solution
- Accurate and timely preparation of Form 1120, 1120-S, and all required schedules.
- Strategic tax planning to minimize liability.
- Expert handling of IRS compliance and state tax requirements.
- Clear communication and proactive updates throughout the process.
The Outcome
- Stress-free tax compliance.
- Lower tax liabilities with smart strategies.
- More time to focus on your business.
- Peace of mind with expert support.
How Corporate Tax Filing at Orbit Works
A clear, structured path from entity review to filed, compliant returns.
01. Entity & Complexity Review
We confirm your entity type, state filing requirements, ownership structure, and reporting complexity.
02. Financials & Documentation Collection
You provide finalized financial statements, prior-year returns, and supporting schedules.
03. Return Preparation
We prepare federal and applicable state returns, including Schedule K-1 (Sch. K-1) where required.
04. Review & Confirmation
We walk through the return with you and confirm filing positions before submission.
05. Filing & Compliance Support
Returns are filed accurately and on time. We assist with notices if needed.
Step 02 · Financials and documentation collection
Exactly What We Will Need From You
You send finalized financial statements, prior-year returns, and supporting schedules. If Orbit already does your bookkeeping, we pull most of this ourselves and only ask you for what is missing.
Business records
- Prior-year federal and state returns
- Year-end financial statements or trial balance, or access to QuickBooks Online or Xero
- Year-end bank and credit card statements
- Loan statements and amortization schedules
- Fixed asset additions and disposals, with invoices
Payroll and contractors
- Forms W-2 and W-3
- Forms 941 or 944, and Form 940
- Forms 1099-NEC and 1099-MISC issued
- Owner salary detail for S corporations
Entity and footprint
- Employer Identification Number (EIN) letter and formation documents
- Form 2553 acceptance letter if you elected S corporation status
- Ownership percentages and any change during the year
- States where you have employees, property, inventory or sales
Most clients send this once, through the Orbit Portal. We chase the gaps, so you are not the one keeping a list.
The Return Is the Output. The Decisions Happen Earlier.
A tax return tells you what last year cost you. A fractional Chief Financial Officer (CFO) changes what next year costs you. Orbit’s CFO team works from the same books that produce your return, so the advice and the filing never disagree.
Entity structure and elections
Whether an S corporation election (Form 2553) or a C corporation structure leaves more cash in the business, and when a change is worth making.
Owner pay and distributions
Setting a reasonable salary that stands up to IRS scrutiny, then balancing it against distributions.
Quarterly estimates
Federal and state estimated payments forecast through the year and revised as results move, so April brings no surprises.
Cash flow and runway
A rolling forecast that shows what the tax bill does to cash before the payment is due.
Which Return Does Your Business File?
Your entity type decides the form, the deadline, and who pays the tax. Here is the whole picture on one screen.
| Business type | Federal return | How the profit is taxed | Deadline (calendar year) | Owners receive |
|---|---|---|---|---|
| Sole proprietor and single-member LLC | Schedule C, filed with Form 1040 | Taxed once, on the owner's personal return. Self-employment tax applies to the profit. | April 15, extended to October 15 | No K-1. Profit flows through Schedule C. |
| Partnership and multi-member LLC | Form 1065 | Pass-through. The entity does not pay federal income tax; each partner reports their share. | March 15, extended to September 15 | Schedule K-1 |
| S Corporation, including an LLC electing S corp status | Form 1120-S | Pass-through. Owner-employees take a reasonable salary through payroll, plus distributions. | March 15, extended to September 15 | Schedule K-1 |
| C Corporation, including an LLC electing C corp status | Form 1120 | Taxed at the corporate level. Dividends are taxed again to shareholders. | April 15, extended to October 15 | Form 1099-DIV, if dividends are paid |
State returns sit on top of the federal return. Some states also charge franchise, excise or gross receipts tax that applies even in a year with no profit.
Every Form, One Map
Choose your structure. We will show you what it files, when it is due, and exactly what reaches your personal return.
Sole Proprietor and single-member LLC
Files Schedule C + Form 1040
Taxed once, on the owner's personal return. Self-employment tax applies to the profit.
What reaches your Form 1040
Plus, for any owner
State returns sit on top of the federal return. Some states also charge franchise, excise or gross receipts tax that applies even in a year with no profit.
Standard or Pro? It Usually Comes Down to Where You Do Business
Nexus is the connection that gives a state the right to tax your business. It used to mean an office or a warehouse. Since the 2018 Supreme Court decision in South Dakota v. Wayfair, most states also apply an economic test based on sales into the state, so you can create a filing obligation without ever setting foot there.
Physical presence
An office, equipment, or inventory in the state, including stock held in a third-party fulfillment warehouse.
People
An employee, a remote hire, or a contractor working from that state. One remote employee is often enough.
Economic activity
Sales into the state above that state's threshold. Thresholds differ by state and change, so we review them each year.
Illinois
Corporations file Form IL-1120, or IL-1120-ST for S corporations, alongside the federal return. Illinois also applies a personal property replacement tax. We prepare both so the state and federal filings agree.
Washington
There is no state corporate income tax, but businesses file Business and Occupation (B&O) excise tax returns with the Department of Revenue, calculated on gross receipts rather than profit. We keep those on schedule with your federal return.
How this maps to the plans. One state, fewer than 10 fixed assets and no foreign reporting fits Standard. Multiple states, more than 10 fixed assets, or foreign reporting moves you to Pro. If you are not sure which describes you, that is exactly what the consultation is for.
Tailored, Transparent Pricing for your Business
Join businesses across the U.S. who trust Orbit
Books not ready for tax season?
One team, one fixed price, no handoff between two firms.
Trusted by high-
growth organizations
"I've been working with Orbit since the beginning of 2026 and couldn't be happier. They are professional, detail-oriented, responsive, and always timely. As the owner of a one-person corporation, I greatly appreciate having such a reliable accounting team in my corner. Highly recommended!"
Maja Djikic
Consultant
Everything your finance function needs, under one trusted partner
From clean books to strategic CFO guidance, Orbit Accountants delivers the full back-office stack for U.S. small and medium-sized businesses. Fixed monthly pricing, on-time month-end, and a dedicated team that actually knows your business.
Bookkeeping & Reconciliations
Maintain pristine monthly financial records with expert categorization and bank reconciliations, so every dollar is accounted for, always.
"Our books went from a mess to perfect within 2 weeks."
What Is Corporate Tax Filing and Why Is It Vital for Businesses?
Corporate tax filing is the process by which businesses report their financial activities, including income, expenses, and deductions, to the IRS. This ensures compliance with federal, state, and local tax laws and helps avoid penalties.
Corporate tax filing keeps your business compliant, ensures accurate tax payments, and protects you from penalties. Here's a closer look at what it involves and how professional, online tax filing services help U.S. businesses save time and stay ahead.
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Frequently Asked Questions
We prepare Form 1120 (C Corporation), Form 1120-S (S Corporation), Form 1065 (Partnership), and Schedule C with Form 1040 for sole proprietors and single-member Limited Liability Companies (LLCs).
Yes, in every form: single-member LLCs reported on Schedule C with Form 1040, multi-member LLCs on Form 1065, and LLCs that elect S corporation or C corporation treatment. We confirm the right election for your situation before we file.
Yes. We prepare Schedule K-1 for each shareholder or partner in S corporations (Form 1120-S) and partnerships (Form 1065), so every owner gets the figures they need for their personal return.
Yes. We prepare personal returns alongside the business return, so your Schedule K-1 flows straight into Form 1040 without a second firm chasing figures. Standard covers a single state with standard income documents. Pro covers itemized deductions, multi-state filing, self-employment and rental income, K-1s, investment activity and foreign reporting.
For calendar-year filers, Form 1120-S and Form 1065 are due March 15, and Form 1120 and Form 1040 are due April 15. An extension moves those dates to September 15 and October 15. If a date falls on a weekend or a federal holiday it shifts to the next business day, and state deadlines can differ. An extension moves the filing date, not the payment date.
Pricing is fixed and organized first by entity type, then by plan. Business returns are billed annually and personal returns are billed per return. You see the price before we start, and it changes only if the scope does.
Standard covers a single state, fewer than 10 fixed assets, and no foreign reporting. It suits an owner running a straightforward business with simple reporting needs.
Pro covers multi-state filing, more than 10 fixed assets, and foreign reporting where it applies. Multiple owners and a higher volume of Schedule K-1 forms usually point to Pro as well.
Fixed. We quote once we understand your entity, states, fixed assets and complexity, and we hold that price for the engagement. There are no hourly bills and no surprise invoices at filing time.
No. Bookkeeping runs on a separate fixed monthly plan. If your books need catch-up work before a return can be prepared, we scope and quote that up front so there is nothing to discover later.
Yes. We run a nexus review, register you where you need to be, apportion income between states, and file each state return. Where a state charges franchise, excise or gross receipts tax instead of income tax, such as the Washington Business and Occupation tax, we handle those filings too.
Three things, usually: physical presence such as an office or inventory, people such as an employee or contractor working there, or economic activity such as sales above that state's threshold. Any one of them can be enough, and thresholds change, so we review your footprint each year.
Foreign reporting is included in the Pro plan where it applies. We confirm exactly which forms your situation requires before we start, so the scope and the price are settled in advance.
Yes. We review the original return, prepare the amended federal and state filings, and explain the likely outcome before anything is submitted.
We start with a catch-up plan: reconstruct the books for each open year, prepare the missing returns in order, and file them together where that makes sense. Coming forward voluntarily is almost always a better position than waiting for a notice.
Prior-year returns, year-end financials or access to QuickBooks Online or Xero, payroll and contractor forms, fixed asset detail, and your ownership and state footprint. The full checklist is on this page. If Orbit does your bookkeeping, we pull most of it ourselves and only ask for the gaps.
No, but the books have to be complete and reconciled. If they are not, we quote catch-up work first, because filing from unreliable books is how errors and amendments happen.
Yes. We calculate federal and state estimates, tell you what to pay and when, and revise the forecast during the year as results move.
Yes. We can prepare a clean year-end package for your existing CPA, or take the filing on ourselves. Plenty of clients start with the first and move to the second.
Yes. Planning sits with our Fractional CFO team: entity structure and elections, owner compensation, timing of purchases, and the quarterly estimate forecast. See Fractional CFO Services.
Send it to us. We review it, explain what triggered it, and prepare the response with the supporting workpapers behind your return.
Disclaimer
The information on this page is provided for general educational purposes only and does not constitute legal, tax, or accounting advice. Federal and state tax rules, IRS guidance, thresholds, and deadlines change and apply differently to each business. Deadlines shown are for calendar-year filers and shift when a date falls on a weekend or a federal holiday. Every business is different, so please consult a qualified professional who has reviewed your specific situation before acting on anything here. Orbit Accountants is not responsible for decisions made based on this general information.
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