Form FTB 3577: Pending Audit Tax Deposit Voucher for Corporations (2024 Instructions)

Form FTB 3577, Pending Audit Tax Deposit Voucher for Corporations, is a payment voucher issued by the California Franchise Tax Board that lets corporations make a deposit against an anticipated tax assessment while an audit or protest is still pending. It’s not a tax return and it doesn’t report income or credits. It’s simply a mechanism for sending money to the FTB ahead of a final determination, so that interest doesn’t keep piling up on whatever amount you eventually owe.

The logic behind this form comes from California’s deposit-versus-payment rules. When a corporation is under audit, disputing a proposed assessment, or waiting on an appeal, interest continues to accrue on any additional tax the FTB believes is due. If the corporation ultimately loses the dispute, that interest can add up significantly. By submitting a deposit with Form FTB 3577, a corporation can stop the interest clock on the deposited amount, even though the case hasn’t been resolved yet. If the corporation wins the audit or the assessment is reduced, the deposit (or the unused portion) is returned; if the corporation owes tax, the deposit is applied against the final liability.

Who Needs to File Form FTB 3577

This voucher applies specifically to C corporations, S corporations, and other entities taxed as corporations in California that are currently involved in an FTB audit, protest, or appeal where additional tax may be assessed. It’s a voluntary tool — nobody is required to make a deposit — but for corporations that expect to lose part or all of a dispute, it’s a straightforward way to limit interest exposure while the matter works its way through the audit or appeals process.

It’s worth noting that this form is strictly for corporations. Limited liability companies facing a similar situation use a parallel form instead — Form FTB 3578, the Pending Audit Tax Deposit Voucher for LLCs, which follows the same basic concept but applies to entities classified as LLCs for tax purposes.

When to Use This Voucher

Form FTB 3577 is typically used after the FTB has proposed an adjustment or additional assessment following an audit, and the corporation intends to protest or appeal that finding rather than pay it outright. Rather than waiting years for the dispute to resolve while interest accrues on the full disputed amount, the corporation submits a deposit for some or all of the contested tax. This is different from simply paying the tax, since a deposit doesn’t concede that the amount is owed — it just neutralizes future interest on that portion while the disagreement continues.

Corporations can also use this voucher proactively, before a formal assessment is issued, if they anticipate that an audit currently underway will result in additional tax. Making a deposit early, as soon as the exposure becomes apparent, is generally the most effective way to minimize interest costs.

How to Fill Out and Submit Form FTB 3577

The form itself is short. Since it has fillable AcroForm fields, you can type directly into the PDF instead of printing it out and writing by hand. You’ll need to provide the corporation’s exact legal name as registered with the FTB, its California corporation number, the tax year under audit, and the dollar amount being deposited. Accuracy on the entity name and ID number matters, since the FTB needs to match the deposit to the correct case file and audit period.

Once completed, the voucher is mailed to the FTB along with the payment, following the mailing address and instructions printed on the form itself. Keep a copy of the completed voucher and proof of payment for your records, since you’ll want documentation showing when the deposit was made if the timing of interest calculations is ever disputed later.

Corporations dealing with exempt organization filings or unrelated business income issues sometimes encounter audit questions tied to Form 109, the California Exempt Organization Business Income Tax Return, which can also lead to a pending audit scenario where a deposit voucher becomes relevant. Whatever the underlying return, the deposit process itself works the same way through Form FTB 3577.

Because this form directly affects how much interest a corporation ultimately pays, it’s generally worth discussing the timing and amount of any deposit with a tax professional familiar with the specific audit or protest, rather than treating it as a routine filing.