US tax
Priced per return agreed before work starts
The quote depends on your entity, the number of owners, whether Form 5472 applies and how many contractors need a 1099.
Get a quoteTax · United States
US business tax preparation services for startups, from books already closed.
Excello's US business tax preparation services cover the federal returns startups file each year: Form 1120 for C corporations, Form 1065 or Schedule C for LLCs, and Form 5472 for foreign-owned LLCs.
Founders' personal returns, contractor 1099s and the Delaware franchise tax sit alongside them, all prepared from books closed inside your own QuickBooks, Xero or Odoo.
- Prepared
- C corps Form 1120
- LLCs 1065 or Schedule C
- Foreign-owned LLCs Form 5472
- Quoted before work starts
The US returns Excello prepares
Scope
Business tax return preparation starts with knowing which returns your company owes. These are the ones Excello prepares, with the deadline for a business whose tax year ends on December 31.
| Return | Who it is for | Due | What it covers |
|---|---|---|---|
| Form 1120 | C corporations, including Delaware C corps | April 15 | The federal corporate return, prepared from your closed books |
| Form 1065 | LLCs with two or more members | March 15 | The partnership return, with a Schedule K-1 for each member |
| Schedule C with Form 1040 | Single-member LLCs owned by a US person | April 15 | The business result, reported on the owner's personal return |
| Form 5472 with a pro forma Form 1120 | Single-member US LLCs owned by a non-US person | April 15 | Reports money moving between the LLC and its owner |
| Form 1040 | Founders | April 15 | Personal returns, prepared alongside the company's |
| Form 1099-NEC | Businesses that paid contractors | January 31 | Prepared from the contractor payments recorded in your books |
| Franchise tax and annual report | Delaware corporations | March 1 | Worked out both ways, so you pay the lower tax |
When a deadline falls on a weekend or a legal holiday, it moves to the next business day.
Why a return starts with closed books
The foundation
Delaware C corp tax filing: the federal return and the state's franchise tax
C corporations
A C corp tax return is Form 1120. Every US C corporation files one each year, whether or not it made money, and pays federal corporate income tax at a flat 21% of taxable income.
It is due by the 15th day of the fourth month after the tax year ends: April 15 for a calendar year. Form 7004 extends the time to file, generally by six months, but tax owed is still due on the original date.
A Delaware corporation also owes Delaware franchise tax and a $50 annual report by March 1. The tax can be worked out two ways, and the lower result is the one you pay. For a startup with millions of authorized shares, that is usually the Assumed Par Value Capital method, with a minimum of $400.
You can check your own figure with Excello's free Delaware franchise tax calculator.
Source: IRS Instructions for Form 1120 (2025) and Form 7004 (December 2025); 26 U.S.C. § 11(b); Delaware Division of Corporations. Checked 22 September 2026.
LLC tax filing: which return does your LLC file?
LLCs
An LLC's return depends on how many owners it has and where they live. The IRS treats a one-owner LLC as part of its owner and a two-owner LLC as a partnership, unless it chooses to be taxed as a corporation.
| Your LLC has | What it files |
|---|---|
| One owner who is a US person | Schedule C with the owner's Form 1040 |
| One owner who is not a US person | A pro forma Form 1120 with Form 5472 attached |
| Two or more owners | Form 1065, with a Schedule K-1 for each member |
| Any LLC that elected to be taxed as a C corporation | Form 1120 |
What is Form 5472, and who needs Form 5472 filing?
Foreign-owned LLCs
Source: IRS Instructions for Form 5472 (Rev. December 2024). Checked 22 September 2026.
The US tax calendar for a startup
Deadlines
For a company and founders whose tax years end on December 31, the year's filings fall in this order.
| Date | What is due |
|---|---|
| January 31 | Form 1099-NEC to each contractor and to the IRS |
| March 1 | Delaware franchise tax and annual report |
| March 15 | Form 1065 for LLCs with two or more members |
| April 15 | Form 1120, Form 5472 with its pro forma Form 1120, and Form 1040 with Schedule C |
| September 15 | Form 1065, when extended |
| October 15 | Form 1120, Form 5472 and Form 1040, when extended |
On 1099 filing: for payments made from 2026, a contractor paid $2,000 or more in the year gets a Form 1099-NEC. Payments made in 2025 used the old $600 threshold.
Source: IRS Instructions for Forms 1099-MISC and 1099-NEC (December 2026), Form 1065 and Form 7004. Checked 22 September 2026.
How US tax preparation works with Excello
Four steps
-
Step 01
Scope
Your entity, owners and which returns apply, then a written quote.
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Step 02
The year closed
Twelve months closed in your QuickBooks, Xero or Odoo, with any catch-up quoted separately.
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Step 03
Returns prepared
Each return prepared from the closed books and walked through with you.
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Step 04
You review and sign
You approve every return before its deadline.
Tax in other countries, and related tools
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The payroll, Delaware franchise tax and R&D tax credit calculators.
Free toolsFrequently asked questions
What do business tax preparation services include?
Business tax preparation services turn a year of books into the returns a company owes. At Excello that means Form 1120, Form 1065 or Schedule C, Form 5472 for foreign-owned LLCs, founders' personal returns, 1099s and the Delaware franchise tax.
When is a C corp tax return due?
A C corp tax return is due by the 15th day of the fourth month after the tax year ends. For a calendar year, that is April 15. Form 7004 extends the time to file, generally by six months, but not the time to pay.
Does a Delaware C corp with no revenue still file a tax return?
Yes. A US C corporation files Form 1120 every year whether or not it had income, and a Delaware corporation also owes the Delaware franchise tax and annual report by March 1, even in a year with no sales.
Does my US LLC need to file Form 5472 if I live outside the US?
Usually yes. A single-member US LLC owned by a non-US person files Form 5472 with a pro forma Form 1120 in any year it has transactions with its owner, including money the owner puts in or takes out. The penalty for not filing is $25,000.
What is the 1099-NEC threshold for 2026?
For payments made in 2026, a business reports nonemployee pay of $2,000 or more to one contractor on Form 1099-NEC. The form goes to the contractor and to the IRS by January 31. Payments made in 2025 used the old $600 threshold.
Can Excello prepare my taxes if another firm keeps my books?
Yes. Your US returns can be prepared from books kept by you or another provider. If those books need fixing first, the catch-up is quoted separately, with the price agreed before work begins.