Tax prep support
C corporation tax preparation support
Finbryn prepares Form 1120 workpapers for C corporations from your closed year-end books, covering book-to-tax adjustments, depreciation and estimated payments, and hands the draft to a credentialed signer before the April 15, 2027 deadline for calendar-year 2026 filers.
Tax working papers
Illustrative client · August 2026
USD
- Year-end books closed and reconciledDone
- Fixed asset and depreciation scheduleDone
- Book-to-tax adjustments listedDone
- Supporting schedules for the preparerIn progress
- Handed to the signer for review and filingNext
Illustrative. An example of the document, not a client's figures.
From closed books to a filed return
A C corporation return starts with a trial balance, not a blank page. We tie your year-end books out to the general ledger, build the book-to-tax adjustment schedule that reconciles net income to taxable income, such as depreciation differences, meals limitations and accrued items, and produce a draft your credentialed signer can actually review line by line.
Deadlines that matter
Calendar-year C corporations file Form 1120 by April 15, 2027 for tax year 2026. Filing Form 7004 gives an automatic six-month extension to October 15, 2027, which extends the paperwork deadline but not the payment one. We prepare the extension filing itself when more time is genuinely needed, rather than leaving it as a scramble.
Multi-entity and holding structures
Corporations with subsidiaries, multiple state footprints or intercompany transactions need consolidation and elimination work before the return can be drafted. We handle that inside your monthly close so the year-end tax workpapers are a continuation of numbers you have already reviewed, not a separate reconstruction.
Estimated payments
We calculate the following year's quarterly estimated payments alongside the current return, so the corporation is not caught paying a large balance plus a fresh set of estimates with no planning behind either number.
Where this fits
If the corporation also has research spend, see R&D credit preparation. If a state footprint is expanding, state registration support covers the paperwork that comes with it. Preparation pricing by entity size is on the pricing page.
Questions
Frequently asked questions: C corporation tax preparation support
When is Form 1120 due?
Calendar-year C corporations file by April 15, 2027 for tax year 2026, with an automatic extension to October 15, 2027 available through Form 7004.
Do you handle multi-state corporations?
Yes, we build the state apportionment workpapers as part of the same close, and pair the return with state registration support where a new footprint needs it.
Who signs the return?
A credentialed preparer or CPA reviews and signs the return we build; representation beyond the filed return follows Circular 230 rules for EAs and CPAs.
Can you prepare the extension if we need more time?
Yes, we prepare Form 7004 well before the original deadline so the extension itself is never the thing that runs late.
What does c corporation tax preparation support actually include, month to month?
C corporation tax preparation support covers trial balance tie-out between your books and the return workpapers, along with book-to-tax adjustment schedule (depreciation, meals, accruals). The work runs inside QuickBooks Online, Xero, NetSuite, Drake Tax or UltraTax CS, the file stays under your own subscription, and a senior principal reviews the output before it reaches you each period.
Do you file the return yourselves?
We prepare it. A credentialed signer or your registered filing partner reviews it and files it.
What do you need from us to start?
Closed year-end books, prior-year return, and fixed-asset or loan details we do not already hold.
How is c corporation tax preparation support priced?
Pricing for c corporation tax preparation support depends on your transaction volume, the software you use, and how much cleanup is needed before ongoing work starts. Current ranges are published on the pricing page, and your exact fee is confirmed in writing before anything begins.
What software works with c corporation tax preparation support?
C corporation tax preparation support runs inside QuickBooks Online or Xero, whichever you already use. If you are not yet set up in either, we can configure a file in your name so you keep ownership of it once the engagement is under way.
Related services
- Tax prep supportEstimated tax payment supportSupport for calculating and scheduling quarterly estimated tax payments so a large bill never arrives as a surprise at filing time.
- BookkeepingMonthly bookkeepingOngoing monthly bookkeeping: transactions sorted into categories, accounts reconciled and month-end reports delivered in the software you already use.
Industries
- ManufacturingBookkeeping for small and mid-size manufacturers tracking raw materials, work in process and finished goods inventory.
- SaaSBookkeeping and reporting for subscription software businesses tracking recurring revenue, deferred revenue and burn.
- Startups and VC-backed companiesBookkeeping and reporting for early-stage, venture-backed companies watching burn, runway and investor reporting closely.
Next step
Talk to the team that would run your books
A short call covers your setup, your software and what a first month would look like. You get a written scope and price after it.