Form 1120 Short Tax Year: How to Fill the Begin/End Dates and Initial Return Box

Applying the Short Tax Year to Form 1120

When you actually fill Form 1120 with a short tax year, the relevant section is at the very top: the tax year fields. The pre-printed form text reads something like "For calendar year 2025 or tax year beginning [field] ending [field]" — and you fill the two date fields with your actual short period.

The Initial Return Checkbox

In the box marked Item E on Form 1120's first page, there's a check box for "initial return" and "final return." Use these to flag the special status of your short tax year:

- **Initial return**: check this if it's your LLC's first tax year. Common for foreign-owned LLCs in their formation year. - **Final return**: check this if it's your LLC's last tax year (dissolution). Both can be checked if it's a single-year LLC formed and dissolved in the same year.

How the Dates Look for an Initial Return

Example: your LLC was formed on July 22, 2025, and you're filing for the short tax year ending December 31, 2025.

Form 1120 setup: - For calendar year [blank — leave the calendar year line empty since you're using the begin/end fields] - OR tax year beginning [07/22/2025] ending [12/31/2025] - Item E checkbox: ✓ Initial return

This tells the IRS: the LLC exists from July 22 onwards, this is the first tax year, the year ends December 31. The IRS processing system reads the dates from the begin/end fields and the checkbox to confirm the short status.

Don't Just Use the Calendar Year Line

Form 1120's first line says "For calendar year [YYYY]." If you have a full calendar year, you fill that line and leave the begin/end fields blank. For a short tax year, do the opposite: leave the calendar year line blank and fill the begin/end fields with the actual short period dates.

Using the calendar year line for a short tax year is misleading — it tells the IRS the LLC existed for the full year, which contradicts the begin/end dates. Some processing systems read the calendar year line first and skip the begin/end fields entirely, which means your short tax year may not be recognized at all.

Cross-Reference with Form 5472

Form 5472 has its own tax year fields that must match Form 1120 exactly. If Form 1120 shows tax year beginning July 22, 2025, Form 5472 must show the same dates.

Mismatched dates across the two forms are a common processing error — the IRS treats them as different filings or asks for clarification. Always cross-check the dates on both forms before mailing/faxing.

The Date Field Goes Across Two Years (For Fiscal Year LLCs)

If your LLC uses a fiscal year instead of a calendar year (uncommon but possible), the begin/end dates may span across two calendar years. For example, a fiscal year from July 1, 2024 to June 30, 2025.

The Form 1120 dates handle this fine — just fill the actual dates regardless of which calendar year they fall in. The IRS uses the fiscal year end (June 30, 2025 in this example) to determine the filing year for processing purposes. Most foreign-owned LLCs don't have fiscal years, so this typically doesn't come up — but if it does, the principle is the same.

Match the Publication 538 Example Pattern

Publication 538's worked example is essentially the template:

"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."

Replace XYZ Corporation with your LLC's name, July 1 with your actual formation date, and you have the structure for your short first tax year filing on Form 1120: enter July 1 as the beginning, December 31 as the ending, check Initial Return, sign, file.