Checklist
Small business tax return checklist for 2026.
The documents to ask business clients for on a 2026 return, from the books to payroll and owners, with the due date for each type of return.
Last updated · Facts checked
This small business tax return checklist covers the documents to ask business clients for on their 2026 federal return. It works for sole proprietors filing Schedule C, partnerships and multi-member LLCs filing Form 1065, and S and C corporations filing Form 1120-S or 1120.
Each group of documents comes with a one-line "why we ask" you can paste into your request. Send each client only the groups that fit their business, and send the partnerships and S corporations first: their returns are due a month before everyone else's.
Before you use these lists
These are typical examples to tailor to each client, not a list of what the IRS requires you to collect. Start from last year's return and the client's books, then:
- Ask for the books first. If a bookkeeper closes the year, most of what you need is in the year-end reports. Ask for the source documents only where the books don't cover it.
- Name the year. "Bank statements for January to December 2026" leaves less room for a missing month than "your bank statements".
- Ask what changed. A new owner, a new vehicle, a first employee, a business sold. Changes are where documents go missing.
- Ask about state returns too. These lists are for the federal return. State income, franchise and sales tax returns can need more.
Which return, and when it's due
For a business whose tax year is the calendar year. A business with a fiscal year counts the same number of months from its own year end.
| Business | Federal return | Due for 2026 |
|---|---|---|
| Sole proprietor or single-member LLC | Schedule C, with the owner's Form 1040 | 15 April 2027 |
| Partnership or multi-member LLC | Form 1065, and a K-1 per partner | 15 March 2027 |
| S corporation | Form 1120-S, and a K-1 per shareholder | 15 March 2027 |
| C corporation | Form 1120 | 15 April 2027 |
An extension moves the 15 March returns to 15 September 2027, and the 15 April ones to 15 October 2027. Extensions are on Form 4868 for individuals and Form 7004 for businesses. They give more time to file, not to pay.
Before those, a business with staff or contractors has its own January deadlines. W-2s go to employees and most 1099-NECs to contractors by 1 February 2027, because 31 January is a Sunday.
The fourth-quarter Form 941 and the annual Form 940 are due the same day. Checked on 24 October 2026 against Publication 509 and the other IRS.gov pages listed under Sources.
Ask partnerships and S corporations first
Their returns, and the K-1s their owners need, are due on 15 March. Ask for their documents by the end of January, or the owners' own returns end up waiting too.
Books and bank
For every business. These are the records the rest of the return is built from.
| Document | Why we ask |
|---|---|
| Year-end profit and loss statement and balance sheet | They summarize the year we're reporting. |
| General ledger or trial balance, exported from your bookkeeping software | So we can trace any figure back to its entries. |
| Bank statements for every business account, January to December | To check the books against what actually moved. |
| Credit card statements for every card used for the business | Business costs paid by card count too. |
| Bank reconciliations for 31 December | They show the books and the bank agree. |
| Loan statements showing the year-end balance and interest paid | Interest is deductible, and the balance goes on the balance sheet. |
Income
| Document | Why we ask |
|---|---|
| Forms 1099-NEC and 1099-MISC the business received | The IRS gets a copy, so we check they match your income. |
| Form 1099-K from payment apps, card processors or marketplaces | It shows payments received through them. |
| Sales records, such as invoices or a sales report | To confirm the year's total sales. |
| Sales tax returns filed for the year (if you collect sales tax) | Sales tax collected isn't your income, so we separate it. |
Expenses
| Document | Why we ask |
|---|---|
| Receipts for large or unusual purchases | Large costs need proof of what they were for. |
| A list of contractors paid, with their Forms W-9 | To check the 1099-NECs you had to send. |
| A mileage log for each vehicle used for the business | Business miles need a record to be deducted. |
| Business insurance statements | Premiums are deductible. |
| Home office size and household bills (sole proprietors working from home) | You may be able to deduct part of them. |
Payroll
For businesses with employees, including owners paid through payroll.
| Document | Why we ask |
|---|---|
| Forms 941 for each quarter, and Form 940 | To match wages and payroll taxes to the books. |
| Forms W-2 and W-3 | They show each employee's pay for the year. |
| A payroll summary report for the year | It ties the forms to the books. |
| Retirement plan contributions made for employees and owners | They're deductible, with their own limits. |
| Health insurance the business paid for owners (S corporations) | It's treated differently from employees' insurance. |
Assets and inventory
| Document | Why we ask |
|---|---|
| Invoices for equipment, vehicles or property bought | To claim depreciation on what you bought. |
| Sale paperwork for any assets sold or scrapped | A sale may mean a gain or loss to report. |
| Last year's depreciation schedule (new clients) | Depreciation continues from where it left off. |
| Inventory count and value at 31 December (if you hold stock) | Unsold stock isn't a cost yet. |
Owners
For partnerships, LLCs and corporations. A sole proprietor's draws are in the bank statements.
| Document | Why we ask |
|---|---|
| Any changes in who owns the business, and when | Each owner's share of income depends on it. |
| Money owners put in or took out during the year | Contributions and distributions are tracked per owner. |
| Loans between the business and its owners | They're reported separately from other loans. |
| Pay for officers and owners (S and C corporations) | Owner pay is reported separately. |
New clients only
| Document | Why we ask |
|---|---|
| Last year's federal and state business returns | Our starting point for this year. |
| The IRS letter confirming the business's EIN | So the return goes under the right number. |
| Formation documents and any partnership or operating agreement | They set out who owns what and how profits are shared. |
| The IRS letter accepting the S corporation election (S corporations) | It confirms which return the business files. |
Copy the full business checklist
2026 SMALL BUSINESS TAX RETURN: DOCUMENT CHECKLIST
For a calendar-year business. Partnerships and S corporations:
due 15 March 2027. Sole proprietors and C corporations: 15 April 2027.
BOOKS AND BANK
- Year-end profit and loss statement and balance sheet
Why we ask: they summarize the year we're reporting.
- General ledger or trial balance, exported from your software
Why we ask: so we can trace any figure back to its entries.
- Bank statements for every business account, Jan to Dec
Why we ask: to check the books against what actually moved.
- Credit card statements for every card used for the business
Why we ask: business costs paid by card count too.
- Bank reconciliations for 31 December
Why we ask: they show the books and the bank agree.
- Loan statements with the year-end balance and interest paid
Why we ask: interest is deductible.
INCOME
- Forms 1099-NEC and 1099-MISC the business received
Why we ask: the IRS gets a copy, so we check they match.
- Form 1099-K from payment apps, card processors or marketplaces
Why we ask: it shows payments received through them.
- Sales records, such as invoices or a sales report
Why we ask: to confirm the year's total sales.
- Sales tax returns filed for the year (if you collect sales tax)
Why we ask: sales tax collected isn't your income.
EXPENSES
- Receipts for large or unusual purchases
Why we ask: large costs need proof of what they were for.
- A list of contractors paid, with their Forms W-9
Why we ask: to check the 1099-NECs you had to send.
- A mileage log for each vehicle used for the business
Why we ask: business miles need a record to be deducted.
- Business insurance statements
Why we ask: premiums are deductible.
- Home office size and household bills (sole proprietors)
Why we ask: you may be able to deduct part of them.
PAYROLL
- Forms 941 for each quarter, and Form 940
Why we ask: to match wages and payroll taxes to the books.
- Forms W-2 and W-3
Why we ask: they show each employee's pay for the year.
- A payroll summary report for the year
Why we ask: it ties the forms to the books.
- Retirement plan contributions for employees and owners
Why we ask: they're deductible, with their own limits.
- Health insurance the business paid for owners (S corporations)
Why we ask: it's treated differently from employees' insurance.
ASSETS AND INVENTORY
- Invoices for equipment, vehicles or property bought
Why we ask: to claim depreciation on what you bought.
- Sale paperwork for any assets sold or scrapped
Why we ask: a sale may mean a gain or loss to report.
- Last year's depreciation schedule (new clients)
Why we ask: depreciation continues from where it left off.
- Inventory count and value at 31 December (if you hold stock)
Why we ask: unsold stock isn't a cost yet.
OWNERS
- Any changes in who owns the business, and when
Why we ask: each owner's share of income depends on it.
- Money owners put in or took out during the year
Why we ask: contributions and distributions are tracked.
- Loans between the business and its owners
Why we ask: they're reported separately from other loans.
- Pay for officers and owners (S and C corporations)
Why we ask: owner pay is reported separately.
NEW CLIENTS ONLY
- Last year's federal and state business returns
Why we ask: our starting point for this year.
- The IRS letter confirming the business's EIN
Why we ask: so the return goes under the right number.
- Formation documents and any partnership or operating agreement
Why we ask: they set out who owns what.
- The IRS letter accepting the S corporation election
Why we ask: it confirms which return the business files.
Client-friendly version
Business owners know their business better than their forms. This version asks in plain words, so they can work through it without calling you. Paste it into your request message and remove what clearly doesn't apply.
Your business's 2026 tax return: what we need from you
This covers 1 January to 31 December 2026. If a bookkeeper keeps
your books, most of this is in their year-end reports. Where the
answer to a question is no, just tell us.
Your books
Send the year-end profit and loss and balance sheet, and the bank
and credit card statements for every business account.
Money in
Send any 1099 forms the business received, from clients or from
payment apps, and your sales tax returns if you file them.
Money out
Send receipts for anything large or unusual, the list of
contractors you paid, and a mileage log if you drive for work.
Did you have employees, or pay yourself through payroll?
Send the payroll reports for the year, including the W-2s.
Did you buy or sell equipment, a vehicle or property?
Send the invoices or sale paperwork.
Did anything change about who owns the business?
Tell us what changed and when, and what each owner put in or took
out during the year.
Please send everything by [due date]. If something isn't ready yet,
send what you have now and the rest when it is.
Sending it
Business returns come in two waves, and payroll records are needed before either.
- Partnerships and S corporations in early January, with a due date at the end of January. That leaves February to prepare, and their owners get their K-1s on time.
- Sole proprietors and C corporations by mid-January, with a due date at the end of February.
- Payroll and contractor records first. If you also prepare the client's W-2s or 1099-NECs, ask for those records in early January, because they're due on 1 February.
For timings and wording, see how often to send reminder emails to clients and the tax organizer email templates.
How to do this in GarnerDocs
Save one template per type of business, then start each client's request from the one that fits.
- A template per return. Schedule C, partnership, S corporation and C corporation, each with only the groups that apply.
- Groups become categories. Your client sees the documents grouped the same way, with "why we ask" under each name as its description.
- Questions that trim the list. Ask "Did you have employees in 2026?" and show the payroll documents only to clients who answer yes.
- Two due dates. Give the 15 March businesses an earlier date than the rest. Each request's countdown turns amber 3 days before it.
- Short answers for facts. An EIN or the date an owner joined can be typed instead of uploaded.
See Ask questions.
Sources
- Publication 509 (2026), Tax Calendars, IRS.gov: due dates for Forms 1065, 1120-S, 1120, 940 and 941, W-2s, K-1s and extensions. Checked on 24 October 2026.
- What kind of records should I keep, IRS.gov: records for income, purchases, expenses and assets. Checked on 24 October 2026.
- General Instructions for Certain Information Returns, IRS.gov: when 1099s are due. Checked on 24 October 2026.
- When to file, IRS.gov: weekend and holiday due dates, and extensions. Checked on 24 October 2026.
This guide is general information, not legal or tax advice. Check the rules that apply to each client, including their state's.
Questions
Which business clients should I ask first?
Partnerships and S corporations. Their returns are due on 15 March, a month before sole proprietors' and C corporations', and their owners need the K-1s from them for their own returns.
If a bookkeeper closes the books, what do I still need from the client?
Usually the year-end reports, the bank and credit card statements, and anything outside the books: asset purchases and sales, ownership changes, and what owners put in or took out.
Do I need receipts for every expense?
Not up front. Ask for the books and the statements, then receipts for large or unusual costs. The IRS expects the business to keep the supporting documents, so it can show them if asked.
Does a single-member LLC need a business return?
Usually not a separate one. By default its income goes on the owner's Form 1040, on Schedule C, unless it has elected to be taxed as a corporation. Check the client's own case.