Most of the cost of a business return is the back-and-forth: a question, a wait, a document, another question. Owners who arrive with the file below get a return in days and a smaller bill, because the preparer spends time on judgment rather than on chasing.
Every entity
- Reconciled books for the year (QuickBooks Online or Xero) or, failing that, every bank and card statement for all twelve months.
- Payment platform annual reports: Stripe, PayPal, Shopify, Amazon, and any 1099-K received.
- Loan statements showing interest paid and year-end balances.
- Fixed asset purchases over $2,500 with dates and invoices; disposals during the year.
- Inventory count at year-end, at cost, if you hold stock.
- Owner transactions: contributions, draws, distributions, loans to or from the owner, with dates.
- Prior year's return, for opening balances and carryforwards.
- State annual report confirmations and any state notices received.
- Any IRS or state correspondence during the year, opened or not.
Sole proprietors and single-member LLCs (Schedule C)
- Home office square footage if claimed, vehicle mileage log, health insurance premiums paid, retirement contributions.
- The owner's other income documents, since the business return is part of the personal one.
Partnerships and multi-member LLCs (Form 1065)
- The operating agreement and any changes to ownership percentages during the year.
- Each partner's contributions and distributions, separately.
- Guaranteed payments to partners.
- Partner residency, especially any non-US partners (withholding applies).
S-corporations (Form 1120-S)
- Payroll reports for the year, W-2s and W-3, quarterly 941s, annual 940.
- Officer compensation, documented as reasonable.
- Shareholder distributions by shareholder, and any loans between shareholders and the company.
- Health insurance for more-than-2% shareholders (it goes on the W-2).
- The S election acceptance letter (CP261) if this is the first year.
C-corporations (Form 1120)
- Everything above, plus capital transactions: shares issued, SAFEs, convertible notes, option exercises.
- Estimated tax payments made during the year.
- Related-party transactions with foreign owners or affiliates (Form 5472 territory).
- Delaware franchise tax calculation inputs: authorised shares, issued shares, gross assets.
Foreign-owned LLCs
- Every transfer between the owner and the LLC, in both directions, with dates and amounts. This is the content of Form 5472.
- The EIN confirmation letter (CP575).
- A description of what the business does and where the work physically happens, for the US-connected income question.
- Last year's fax transmission report, if a 5472 was filed before.
Questions a preparer will ask anyway
Did anything change in ownership or entity type? Did you hire anyone, in any state? Did you sell into new states? Did you receive any notices? Did you pay any contractor $600 or more? Did the business hold or transact in digital assets? Having the answers ready is the difference between a two-day turnaround and a two-week one.