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Key takeaways
- Most delays come from a handful of missing items: a late K-1, a forgotten brokerage account, or estimated-payment records.
- Your books should support every business number — a year-end profit and loss plus a balance sheet is the core.
- Last year's return is the best checklist you have: every account on it should appear again or be explained.
Every spring, returns stall for the same reasons. Not because anything is complicated, but because one form is missing and nobody noticed until the week of the deadline. Here's the checklist we use with clients, organized the way your preparer will work through it.
Income documents
- W-2s from any employer, including your own S-corporation.
- 1099-NEC and 1099-MISC forms from clients. Keep in mind you may not receive one for every client — your own records should show all income.
- 1099-K forms from payment apps, processors or marketplaces.
- 1099-INT, 1099-DIV and 1099-B (often a combined "composite" 1099) from banks and brokerages.
- Schedule K-1s from partnerships, S-corporations, trusts or estates you have an interest in.
- 1099-R for retirement distributions and SSA-1099 for Social Security benefits.
- Records of digital asset sales, exchanges or income, including exchange reports.
- Rental income summaries and property-management statements.
Business records
- Year-end profit and loss statement and balance sheet, reconciled to bank and card statements.
- Payroll reports: annual summary, quarterly Form 941s and your W-3.
- Fixed-asset purchases and sales with invoices, dates placed in service and business-use percentage.
- Vehicle records: a mileage log showing total and business miles, or actual expenses if you use that method.
- Home office details: square footage of the office and of the home, plus rent or mortgage interest, utilities, insurance and repairs.
- Inventory counts and cost of goods sold, if you sell products.
- Loan statements for business debt, showing interest paid.
- Copies of the 1099s you issued to contractors.
Deductions and credits
- Estimated tax payments — dates and amounts for every federal and state payment, including any overpayment applied from last year.
- Retirement contributions: SEP, Solo 401(k), IRA and HSA contribution records.
- Health insurance premiums if you're self-employed, and Form 1095-A if you bought coverage through a marketplace.
- Mortgage interest (Form 1098) and property tax statements.
- State and local income tax paid, including any pass-through entity tax paid by your business.
- Charitable contributions with receipts; appraisals and Form 8283 support for large non-cash gifts.
- Childcare and education expenses with provider tax IDs, and Form 1098-T for tuition.
- Energy-related purchases if you're claiming a credit, with manufacturer certifications.
Entity and prior-year items
- Last year's federal and state returns, including all schedules.
- Carryovers — capital losses, net operating losses, passive losses, charitable contributions.
- Entity documents for new businesses: formation papers, EIN letter and any S-corp election acceptance letter.
- Ownership changes during the year, including buy-ins, buyouts and capital contributions.
- Any IRS or state notices received during the year.
- Life changes: marriage, divorce, a new dependent, a move to a new state, or the purchase or sale of a home.
When forms arrive
| Form | Usually arrives by |
|---|---|
| W-2, 1099-NEC | Early February |
| 1099-K, 1098, most 1099-INT and DIV | Early to mid February |
| Brokerage composite 1099s | Mid February to March, often with corrections |
| K-1s from partnerships and S-corps | March — or September if the entity extends |
If you have K-1s from investments, plan on an extension. Filing on time with a missing K-1 and then amending costs more than extending and filing once — just remember an extension gives you more time to file, not more time to pay.
In the ExcelTax Vault, each item on this list becomes a task. Upload a document and it's checked off; anything outstanding shows up in your weekly reminder.
This article is general information, current as of September 2026, and isn't tax advice for your situation. Figures are federal unless noted, and indexed amounts change each year — confirm current numbers with your tax pro before acting.