Corporate Tax Return Preparation Checklist

Pull the current-year engagement letter from Practice Ignition or TaxDome. Scope must explicitly cover the federal return, named state returns, and any 7004 extension. Prior-year letters do not roll forward automatically — a missing current-year letter is a Circular 230 problem if the return is filed.

Confirm the entity classification against the prior-year return and any Form 2553 / 8832 elections in the permanent file. C-corps file Form 1120 by April 15; S-corps file Form 1120-S by March 15. A late-March discovery that the client revoked S-status mid-year is the kind of surprise that blows the deadline.

Export the post-close trial balance from QuickBooks Online, Xero, or Sage Intacct as of the fiscal year-end. Import into the workpaper file (CCH Engagement, Caseware, or your firm's templated workbook). Confirm the period is locked in the GL before importing — re-imports after AJEs cause version drift.

Tie every bank and credit-card account to the December (or fiscal year-end) statement. Investigate uncleared items older than 30 days and any $1,000+ reconciling items. Stale outstanding checks need a written-off entry before the books are tax-ready.

Run the A/R and A/P aging reports as of year-end and tie totals to the GL control accounts. Document any variance on the lead schedule. Bad-debt write-offs identified here become a Schedule M-1 reconciling item if the books are accrual but the return is cash-basis.

Update the depreciation schedule for current-year additions, dispositions, and impairments. Tie ending accumulated depreciation to the GL. Book vs. tax depreciation differences feed Form 4562 and the M-1 reconciliation downstream.

Send the prepared-by-client request list via Suralink, TaxDome, or Liscio with a hard internal deadline 30 days before the filing date. Track weekly with the controller — half-complete PBC at fieldwork start is the #1 cause of fee overruns.

Pull December statements for every operating, savings, and brokerage account, plus 1099-INT, 1099-DIV, and 1099-B from each broker. Cross-check against the GL — undisclosed accounts surface here when interest income doesn't match.

Collect Q1–Q4 941s, the 940, all state UI / withholding returns, and the W-3 totals from Gusto / ADP / Paychex. Wages on the W-3 should tie to wages on the 941s and to GL salary accounts; a variance usually means a missing fringe-benefit accrual.

Confirm 1099s were filed by January 31 for every non-corporate vendor paid more than $600 for services. Missing W-9s in the vendor master mean 1099 obligations that quietly slipped — the IRS penalty is per form per year.

Reconcile book net income to taxable income line-by-line: meals disallowance, fines/penalties, tax-exempt interest, federal income tax expense, depreciation differences, accrual-to-cash adjustments. Use Schedule M-3 if total assets are $10M+.

Confirm the COA separates 100% deductible categories (employee snacks, office events) from 50% deductible business meals. Entertainment remains fully nondeductible post-TCJA. A single "Meals & Entertainment" account dumped into a 50% adjustment overstates the disallowance.

Apply Section 179 expensing within the annual cap and taxable-income limitation, then layer bonus depreciation on remaining qualifying property at the current-year phase-down percentage. State conformity varies — many states decouple from bonus and require an addback.

Build the sales, payroll, and property factors for each nexus state. Sourcing rules differ — most states use market-based sourcing for services, a few still use cost-of-performance. Document the source data so the workpaper survives a state audit.

E-file Form 7004 by the original due date with a reasonable estimate of tax due paid via EFTPS. An extension with no payment when balance is owed still triggers failure-to-pay penalties even though late-filing penalty is avoided.

Roll the prior-year file forward in UltraTax, Lacerte, ProSystem fx, or Drake. Import the trial balance via the GL bridge, then post each M-1 adjustment as a tax-only entry so book-to-tax differences are transparent in the workpaper.

Generate every state return where the entity has filing nexus, including PTET elections (NY, CA, NJ and ~30 others) where they're advantageous. Don't forget local returns — Philadelphia BIRT, NYC GCT, Detroit, Portland Metro, etc. ride alongside the state.

Run the diagnostics report and resolve every red (critical) and yellow (warning) item. Critical diagnostics will reject at e-file; warnings often surface real issues — basis missing, EIN mismatch, K-1 percentages not summing to 100.

Block a 60-minute slot with the signing partner once diagnostics are clear. Bring the trial balance, M-1 reconciliation, depreciation schedule, and any unresolved technical questions. Avoid the 48-hours-before-deadline scramble.

Resolve every review note in the workpaper file with a written response. Re-run diagnostics after substantive changes — late edits often introduce new criticals. Leave the review-note thread in the file for permanent documentation.

Deliver the signature-ready PDF via TaxDome, DocuSign, or Liscio. Form 8879-C (or 8879-S) authorizes e-filing and must be signed before transmission — never e-file on a verbal go-ahead.

Transmit through the tax software and monitor for IRS / state acknowledgements. A return is not filed until the ACK shows accepted — submitted returns can reject for trivial reasons (PIN mismatch, dependent SSN issue) and need re-transmission within the perfection period.