28.2 Filing Extensions, International Forms & Cash Reporting

A filing calendar begins with entity identity

Calendar-year partnerships and S corporations generally file income-tax returns by the fifteenth day of the third month after year-end. Calendar-year C corporations generally file by the fifteenth day of the fourth month. For 2025 calendar-year Forms 1065 and 1120-S, the ordinary deadline is March 16, 2026 because March 15 is Sunday. Form 7004 generally supplies six additional months to file these business returns when timely submitted; payment obligations are not automatically deferred.

Due-date rules vary for particular fiscal years and return types. A trust's Form 1041 extension is generally five and one-half months, not the six-month rule assumed for many businesses. Keep original and extended deadlines separately. A disaster postponement, if applicable, is another distinct rule supported by an IRS announcement rather than an informal extension requested from a lender or bookkeeper.

For a C corporation, failure to file generally incurs a percentage of unpaid tax; failure to pay can apply separately. For partnerships and S corporations, per-owner monthly late-filing penalties can arise even when the entity has no ordinary income tax due. The 2025 Form 1065 and 1120-S instructions use $255 per partner or shareholder per month or part of a month, up to twelve months, for the respective return penalties, subject to applicable relief. A zero tax balance does not establish a zero filing penalty.

Form 8300 cash reporting

A trade or business generally files Form 8300 when it receives more than $10,000 in cash in one transaction or related transactions. Cash includes currency and, in designated circumstances, certain cashier's checks, bank drafts, traveler's checks, and money orders with face amounts of $10,000 or less. An ordinary personal check or a bank wire is not cash merely because it produces readily available funds.

File within 15 days after the payment causing the reporting threshold to be exceeded. Related transactions within 24 hours are aggregated, and transactions outside that period can still be related when the recipient knows or has reason to know they are connected. Installment receipts can create a filing duty once the aggregate reportable cash exceeds the threshold under the applicable twelve-month rules. Splitting a payment into $6,000 and $5,000 does not reliably avoid reporting.

Example: A dealer receives $7,000 currency on Monday and $5,000 currency on Tuesday toward the same equipment purchase. The business has received $12,000 in related cash payments and generally files Form 8300 within 15 days after Tuesday's payment. The form is separate from including the sale in taxable revenue. Reporting the sale on Form 1120 does not replace Form 8300.

Provide the required customer statement by January 31 of the following year, subject to ordinary weekend and holiday rules. Preserve the form and support, including the identity information requested by its instructions. Form 8300 electronic-filing requirements can depend on the business's aggregate information-return filing obligation. Do not confuse this report with a bank's separate currency-transaction report.

International information returns

These forms have specific ownership, attribution, transaction, and exception rules. A foreign-owned U.S. disregarded entity can have Form 5472 obligations with a pro forma Form 1120 even when it has no ordinary corporate income-tax return. A partner's foreign address is not itself proof that every international form in the table is required.

Foreign financial accounts can also require FBAR, filed electronically with FinCEN, when a U.S. person's aggregate foreign-account maximum values exceed $10,000 during the calendar year. Its annual deadline and automatic extension rules differ from those of an income-tax return. Form 8938 is an IRS report with different thresholds and coverage; it does not automatically replace FBAR. Some entities, as well as individuals, can have foreign-account reporting obligations.

Payment and compliance advice

Income-tax estimates, payroll deposits, excise-tax deposits, and information returns use different schedules. Form 720 generally reports quarterly federal excise taxes on specified activities, with deposit rules that can require payment before the return's due date. Identify whether the business actually engages in a taxable activity, such as specified fuel or transportation transactions, instead of imposing Form 720 on every business.

For a new foreign investor or large cash customer, obtain the facts before year-end. Missing international information returns can carry substantial fixed penalties and extend limitations periods independently of income-tax liability. Reconcile ownership records, cash receipts, foreign accounts, and related-party ledgers with the return calendar rather than relying on the tax-software interview to discover all obligations.

Official references

IRS Form 8300 reference guide, 2025 Form 1065 instructions, and IRS international information reporting, checked October 17, 2026.

Withholding and excise deposits

A partnership with effectively connected taxable income allocated to foreign partners can owe §1446 withholding even when it makes no cash distributions. Investigate Forms 8804, 8805, and 8813 and the partner’s corporate or noncorporate status. Foreign transferors of partnership interests can also trigger §1446(f) withholding on the amount realized unless an exception or valid certification applies. Information returns alone do not discharge a withholding obligation. See Publication 541.

For many Form 720 excise taxes, deposits generally are required semimonthly when the quarterly net tax liability exceeds $2,500, subject to the tax’s specific exceptions and deposit method. Under the regular method, the first semimonthly period is days 1–15 and the second is day 16 through month-end; deposits generally are due by the fourteenth day after the period ends. September has special rules. Certain taxes are paid with the quarterly return rather than deposited, and communications and air-transportation taxes can use alternative methods. Identify the tax first, then use Publication 510 and the Form 720 instructions for the applicable deposit schedule. The quarterly return deadline does not by itself establish when every payment is due.