IRS Publication 538: Worked Examples for Calendar Year, Fiscal Year, Short Tax Year

Diving Into Publication 538: The Accounting Period Definitions

Publication 538 is structured around two big themes: accounting periods (which tax year you use) and accounting methods (cash vs. accrual). For foreign-owned LLC owners filing the pro forma 1120 + Form 5472, the accounting period chapters are the relevant ones.

Key definitions from the publication:

- **Calendar year**: 12 consecutive months beginning January 1 and ending December 31 - **Fiscal year**: 12 consecutive months ending on the last day of any month except December (or a 52–53 week tax year) - **Short tax year**: any tax year of less than 12 months

How You Adopt a Tax Year

Publication 538 explains how taxpayers adopt accounting periods, but a pro forma Form 1120 used only to transmit Form 5472 is not an ordinary corporate income-tax return and does not automatically give a disregarded entity a freely chosen corporate tax year.

Determine the reporting period from the entity-classification rules, the owner's tax year and applicable required-year rules, prior filings, and the current Form 5472 instructions. Do not create a fiscal year merely by typing dates on the pro forma wrapper. An actual corporation or partnership follows its own accounting-period rules.

Calendar Year Is the Default

The calendar year runs January 1 through December 31 and is common for individual owners. For a domestic LLC disregarded into its foreign owner, the reporting period generally follows the applicable owner and federal required-year rules rather than an independent LLC preference.

An LLC taxed as a partnership or corporation has separate accounting-period rules. Home-country reporting can use a different period, so maintain a reconciliation rather than assuming the U.S. LLC can choose whichever year is convenient.

Short Tax Year Trigger: Not Existing for the Entire Year

Publication 538 explicitly addresses the short tax year trigger: "A short period tax return may be required when you (as a taxable entity) are not in existence for the entire year, or you change your accounting period."

So if your entity didn't exist for the entire year (you formed it mid-year, or dissolved it mid-year), a short period tax return is required. The general rule: even when an entity wasn't in existence for the entire year, a return is still required for the time it WAS in existence. Filing requirements and tax computations are generally the same as for a full tax year ending on the last day of the short period.

Worked Example from Publication 538

Publication 538 provides a classic worked example:

"XYZ Corporation was organized on July 1 and elected a calendar year as its tax year. The corporation's first return will cover the short period from July 1 through December 31."

That's the formation scenario. The mirror example for dissolution:

"A calendar year corporation that dissolved during the year — the final return will cover the short period from January 1 through the date of dissolution (e.g., July 23)."

Both examples follow the same rule: enter the actual beginning and ending dates of the entity's existence during the tax year. The IRS has no special form for short tax years — you use the same Form 1120, just with shorter date ranges in the tax-year fields.

Why Foreign Owners Should Know This

For foreign owners forming their first U.S. LLC, the initial period is often a short tax year. Formation, owner-paid costs, or an initial contribution commonly create a Form 5472 reportable transaction in that period.

Use the actual beginning and ending dates and the initial-return indicator required by the current forms. For a calendar-year period ending December 31, a required pro forma Form 1120 and Form 5472 are generally due April 15; request the ordinary filing extension with a timely Form 7004 rather than assuming a June 15 foreign-owner extension.