Small Business Tax Preparation Checklist: Schedule C, 1120-S and 1065 Intake

9/23/2026

An individual return can usually be prepared from documents. A business return cannot. It is prepared from books, and the quality of the return is capped by the quality of the books it starts from. That is why business return intake looks different from individual intake: the question is not "do we have every form?" but "are these books finished, and do they agree with everything outside them?"

This checklist is for practitioners taking in small business returns: sole proprietors on Schedule C, S corporations on Form 1120-S and partnerships on Form 1065. It is not a list of deductions for owners. It is the set of things a firm should confirm before a business file goes to a preparer, organized so that the file either moves forward complete or goes back to the client with one clear list of what is missing.

Why Business Intake Fails

Three patterns account for most business-return rework.

The books were not closed. The client sends a trial balance in February that still has uncategorized transactions, unreconciled accounts and no year-end adjustments. The preparer becomes the bookkeeper, at return-preparation rates the client did not agree to.

The books disagree with the outside world. Payroll reports do not tie to the ledger. The 1099-K total does not tie to sales. The loan balance does not tie to the lender's statement. Each disagreement is a question that should have been asked at intake.

Owner-level information is missing. Basis, capital accounts, owner compensation, owner-paid expenses and distributions are the items that cross from the entity to the owner's return. They are also the items most likely to be wrong or absent.

The checklist below is built around those three failures.

Before Anything Else: Engagement and Deadlines

Signed engagement letter for the entity, separate from the owners' individual engagements, naming who at the entity can authorize the work
Scope confirmed: entity return, state returns, owner K-1s, any payroll or information-return work
Calendar-year S corporation and partnership returns: due on the 15th day of the 3rd month after year-end (March 15 for calendar-year entities), moved to the next business day if that date falls on a weekend or legal holiday
Extension decision made early for entities whose books will not be ready, so Form 7004 is filed on time

The late-filing penalty for S corporations and partnerships is computed per shareholder or partner, per month. Rev. Proc. 2025-32 sets the base amount at $260 for returns required to be filed in 2027. A ten-owner partnership that files three months late without reasonable cause is looking at a five-figure penalty for a return that may show no tax due. Our partnership tax return deadline checklist covers the March 15 crunch in detail.

1. Books Closed

The first gate. If the answer to any of these is no, the file is not ready.

[ ] All bank and credit card accounts reconciled through year-end, with reconciliation reports provided
[ ] No uncategorized or suspense-account balances remaining
[ ] Loan balances agree to lender year-end statements, with interest and principal split
[ ] Accounts receivable and payable reviewed, if the entity uses the accrual method
[ ] Inventory counted or otherwise determined at year-end, where inventory is material
[ ] Owner draws, contributions and distributions posted to equity, not to expense
[ ] Personal expenses paid by the business identified and reclassified
[ ] Year-end trial balance, profit and loss and balance sheet provided in a format your firm can import

For S corporations and partnerships, the balance sheet matters on the return itself. Form 1120-S, Schedule B, question 11 and Form 1065, Schedule B, question 4 each set out conditions (receipts, assets and, for partnerships, timely K-1s and no Schedule M-3) under which the balance sheet and reconciliation schedules are not required. Many small entities meet them. But the books still need to support the return, and an entity that does not meet the test will need a Schedule L that ties to its books and to the prior year's ending balance.

2. Income Agreed to Outside Sources

[ ] Gross receipts compared to Forms 1099-K from payment processors and marketplaces
[ ] Gross receipts compared to Forms 1099-NEC and 1099-MISC received
[ ] Deposits compared to recorded revenue, with transfers and loans excluded
[ ] Sales tax collected excluded from revenue, if recorded gross
[ ] Other income identified: interest, rents, gains on asset sales, insurance recoveries, forgiven debt

Thresholds matter here because they change what you can tie to. Under the One Big Beautiful Bill Act (P.L. 119-21), Form 1099-K reporting by third-party settlement organizations reverted to more than $20,000 and more than 200 transactions, and the reporting threshold for Forms 1099-NEC and 1099-MISC rose to $2,000 for payments made after December 31, 2025. Smaller businesses will receive fewer forms. The revenue test shifts from "agree the 1099s" to "agree the deposits."

For Schedule C clients in particular, the IRS due diligence rules for credit returns specifically ask preparers to consider whether a Schedule C is complete and correct when it supports the earned income credit or other covered benefits. A sole proprietor with receipts and no expenses, or expenses and no records, is a follow-up question, not a return.

3. Payroll Reconciled

Payroll is where small business books most often disagree with filed reports, because the payroll provider files the reports and the bookkeeper records something else.

[ ] Wages per the ledger agree to the four quarterly Forms 941 (or the annual Form 944) and to Form W-3
[ ] Employer payroll taxes per the ledger agree to the filed reports and to FUTA (Form 940)
[ ] State withholding and unemployment filings agree to the ledger
[ ] Officer or owner compensation identified separately
[ ] Retirement plan contributions and health insurance premiums identified, with owner amounts separated
[ ] Any payroll tax notices received during the year provided

For S corporations, two owner items need specific attention. Reasonable compensation: shareholder-employees who perform services should receive wages, and an S corporation paying distributions with little or no owner salary is a well-known examination issue. Health insurance for more-than-2% shareholders: premiums paid by the corporation are generally included in the shareholder's W-2 wages, so check that the W-2 reflects them before the owner's return is prepared. Our post on payroll setup for new S corporation elections and the year-end payroll reconciliation checklist go deeper on both.

Sole proprietors on Schedule C do not pay themselves wages, but they may have employees, and the same reconciliation applies to them.

4. Information Returns Issued

The business is a payer as well as a payee. Intake should confirm it met its own filing obligations.

[ ] List of contractors and other vendors paid during the year, with amounts
[ ] Forms W-9 on file for each payee
[ ] Forms 1099-NEC and 1099-MISC issued where required, with copies provided
[ ] For 2026 payments, the $2,000 threshold applied (payments made after December 31, 2025), not the old $600
[ ] Payments by card or through payment apps identified, since those are generally reported by the processor rather than the payer
[ ] Backup withholding applied where a payee failed to provide a taxpayer identification number

Two questions arise here every year. First, did the client issue the forms at all? A business that paid contractors and filed nothing has a penalty exposure and, in many cases, a classification question. Second, are those contractors actually contractors? A seasonal worker in the client's shop, on the client's schedule, using the client's equipment, may be an employee whatever the 1099 says. Our post on employee vs independent contractor classification covers the tests.

5. Fixed Assets

[ ] Fixed asset additions listed with date placed in service, cost, description and new or used status
[ ] Invoices provided for significant additions
[ ] Disposals, trade-ins, casualty losses and assets taken for personal use identified
[ ] Vehicles: business-use percentage and mileage records
[ ] Repairs over the firm's capitalization threshold reviewed for capitalization vs expense
[ ] Prior-year depreciation schedule rolled forward and agreed to the balance sheet

The current rules give owners a lot of choice, which means the preparer needs to know the owner's preferences before preparing the return.

Bonus depreciation. The One Big Beautiful Bill Act reinstated the 100% special depreciation allowance for qualified property acquired and placed in service after January 19, 2025. The Form 4562 instructions note that a taxpayer can elect a 40% allowance (60% for long production period property and certain aircraft) instead of 100% for property in the first tax year ending after January 19, 2025. The acquisition date therefore matters, not only the placed-in-service date.

Section 179. For taxable years beginning in 2026, Rev. Proc. 2025-32 sets the section 179 limit at $2,560,000, reduced by the amount by which qualifying property placed in service exceeds $4,090,000. Section 179 is limited by business taxable income; bonus depreciation is not. Owners with losses, or with state returns that do not conform to federal bonus, need a decision rather than a default.

De minimis safe harbor. Many small businesses without an applicable financial statement can elect to expense items up to $2,500 per invoice or item under the de minimis safe harbor in the tangible property regulations. Confirm whether the election is being made and that the books treat small purchases consistently.

Domestic research costs. The 2025 law added section 174A, restoring a current deduction for domestic research or experimental expenditures for tax years beginning after December 31, 2024. Software development and product work are common sources in small businesses. Ask.

6. Owner Basis and Capital

This is the section where the entity return becomes the owner's problem, and the one most often skipped at intake.

S corporations

[ ] Shareholder stock basis and debt basis schedules rolled forward from the prior year
[ ] Shareholder loans to the corporation documented, with repayments identified
[ ] Distributions by shareholder, in proportion to ownership (disproportionate distributions are a single-class-of-stock warning sign)
[ ] Form 7203 information prepared for shareholders who claim a loss, receive a non-dividend distribution, dispose of stock or receive a loan repayment, since each triggers the filing requirement

Partnerships and multi-member LLCs

[ ] Partner capital accounts rolled forward on the tax-basis method used for Schedule K-1, item L
[ ] Contributions and distributions by partner, including property contributed or distributed
[ ] Partnership liabilities allocated among partners
[ ] Changes in ownership during the year, with dates
[ ] Guaranteed payments identified separately from distributions
[ ] The partnership agreement on file, and any amendments affecting allocations

Sole proprietors

[ ] Owner contributions and draws separated from business income and expense
[ ] Home office, vehicle and other mixed-use items supported with records

When the prior preparer did not maintain basis, do not guess. Reconstructing basis from historical returns is a separate piece of work, and the engagement letter should say so.

7. Owner-Paid and Mixed Expenses

[ ] Expenses the owner paid personally for the business identified, with receipts
[ ] For S corporations and partnerships, whether those are reimbursed under an accountable plan, or must be handled as unreimbursed partner expenses where the partnership agreement allows
[ ] Meals, travel and vehicle expenses supported with the substantiation the rules require
[ ] Personal items paid by the business identified and reclassified to distributions or draws

S corporation shareholder-employees who pay business expenses personally generally cannot deduct them on their own returns. The fix is an accountable plan at the corporate level. Our post on accountable plan expense reimbursement rules covers the requirements.

8. Other Entity-Level Items

[ ] Prior-year federal and state returns, for new clients
[ ] Estimated tax payments made by the entity (where applicable) and by owners
[ ] State filing obligations, including new states where the business has employees, property or sales
[ ] Pass-through entity tax elections made or planned at the state level, and payments made
[ ] Notices from the IRS or states during the year
[ ] Loans, grants or credits received, and any forgiveness
[ ] Ownership information that has changed, including new owners and transfers

On beneficial ownership reporting: FinCEN's March 2025 interim final rule exempted entities created in the United States from BOI reporting under the Corporate Transparency Act. Clients who saw older warnings may still ask about it. Confirm the current status on FinCEN's site before advising, since the rule was interim.

A Short-Form Intake Table

Area	Gate question	Typical document
Books	Are all accounts reconciled at year-end?	Reconciliation reports, trial balance
Income	Does revenue agree to deposits and 1099-Ks?	Bank statements, 1099-K, sales reports
Payroll	Do wages agree to 941s and W-3?	Payroll provider year-end reports
1099s	Were required forms issued?	1099 copies, W-9s
Assets	Are additions and disposals listed?	Invoices, asset register
Basis	Are owner basis and capital rolled forward?	Basis schedules, capital account workpapers
Owner items	Are owner-paid and personal items separated?	Receipts, reimbursement reports
States	Have new filing obligations been identified?	Payroll, property and sales by state

Running the Process

Send the business checklist in early January with a books-closed date, not a documents date. A business client who understands the file is not ready until the books are reconciled will plan the bookkeeping around that date. Clients who cannot meet it go on the extension list at intake, with Form 7004 scheduled, rather than discovered in March.

When the file arrives, the completeness check runs against this list. Send one missing-item list, then hold the file until it clears. The preparer's time is too expensive to spend finishing the client's bookkeeping in pieces.

Skills Behind the Checklist

A checklist tells a preparer what to look for. It does not tell them what the answer means. Staff who prepare business returns need to understand how entity choices flow through to owners. The Small Business I Income Tax Preparation Course is the starting point for business return preparation, with Small Business II as the follow-on. For entity-specific depth, see the S Corporations, Sole Proprietorship and Certificate in Partnership Taxation courses.

Next Steps

Turn this checklist into your firm's business intake form, one version per entity type, and send it with the engagement letter. Set a books-closed date, decide extensions at intake, and make the completeness check a gate. For preparers moving from individual to business returns this season, begin with the Small Business I Income Tax Preparation Course.

Frequently Asked Questions

What documents do I need to prepare a small business tax return?

For the preparer, the core is a closed set of books: year-end trial balance, profit and loss, balance sheet and bank and credit card reconciliations. Around that, you need payroll year-end reports and filed Forms 941 and W-3, Forms 1099-K and 1099 received, copies of 1099s the business issued, loan statements, a fixed asset list with invoices, prior-year returns and depreciation schedules, and owner-level items such as basis schedules, capital accounts, distributions and owner-paid expenses. For partnerships, include the partnership agreement. New clients should also supply prior-year federal and state returns.

How is a business return checklist different from an individual checklist?

An individual checklist is mostly about collecting documents that third parties issue. A business checklist is about confirming that the client's own books are finished and agree with outside sources: bank statements, payroll filings, information returns and lender statements. It also covers items that only exist at the business level, such as owner compensation, fixed assets, basis and capital accounts, and the business's own information-return obligations. The most common business intake failure is not a missing form but books that were never reconciled.

When are S corporation and partnership returns due?

Form 1120-S and Form 1065 are due on the 15th day of the third month after the end of the tax year, which is March 15 for calendar-year entities, moved to the next business day if it falls on a weekend or legal holiday. Form 7004 provides an automatic extension of time to file. The late-filing penalty for both is computed per shareholder or partner per month; Rev. Proc. 2025-32 sets the base amount at $260 for returns required to be filed in 2027. Because the penalty applies even when no tax is due, an entity whose books are not ready should be extended on time.

When does an S corporation shareholder need Form 7203?

Form 7203 reports S corporation shareholder stock and debt basis. Under the instructions, a shareholder must file it when claiming a deduction for a share of an aggregate loss (including a loss suspended in a prior year by basis limits), receiving a non-dividend distribution, disposing of stock, or receiving a loan repayment from the corporation. The instructions also suggest completing and retaining it in years when it is not required, so basis stays current. At intake, that means requesting the prior basis schedules and the current year's distributions and loan activity by shareholder.

What changed for 1099 reporting by small businesses?

Under the One Big Beautiful Bill Act, the general reporting threshold for Forms 1099-NEC and 1099-MISC rose from $600 to $2,000 for payments made after December 31, 2025, with inflation indexing from 2027. The Form 1099-K threshold for third-party settlement organizations reverted to more than $20,000 and more than 200 transactions. Businesses will issue and receive fewer forms. The income is still taxable, so intake should test revenue against deposits rather than relying on 1099s to show the full picture.

Should the firm close the client's books as part of the return?

Only if the engagement says so and the fee reflects it. Year-end bookkeeping, reconciliations and adjusting entries are separate work from return preparation, and treating them as part of the return is a common reason business returns run late and over budget. Many firms offer a year-end close service separately and set a books-closed date for clients who do their own bookkeeping. If the books arrive unreconciled, send the file back with a clear list, or quote the cleanup as an additional engagement before starting.