Can I use a period in an IRIS CSV address?

No. Address lines may only contain letters, numbers, hyphens, slashes and spaces.

Is # allowed in a business name?

The formatting guidelines allow it, but Publication 5717 tells filers to remove hashtags from name and address lines. Removing it is the safe choice.

Periods and # in names and addresses

"418 W. Elm St. #2B" has three characters the address field does not allow.

Field	Allowed characters (tax year 2025 guidelines)
Address line 1 and 2	Letters, numbers, hyphen (-), slash (/), space
City	Letters and spaces only
First, middle, last name, suffix	Letters, spaces, hyphens
Business name line 1	Letters, numbers, space, hyphen, pound (#), parentheses, ampersand (&), apostrophe
Business name line 2	Line 1's list plus slash (/) and percent (%)

The two IRS documents differ on #

The formatting guidelines allow a pound sign in a business name. Publication 5717 says to "ensure there are no periods (.) or hashtags (#) in the address or name lines". Perfrow takes the stricter reading and removes both everywhere.

Common cases

In your sheet	Written as
St. Louis	St Louis
Winston-Salem (city)	Winston Salem
O'Brien (last name)	OBrien
Smith & Sons, Inc.	Smith & Sons Inc
P.O. Box 19	PO Box 19
Apt #4	Apt 4
Núñez	Nunez

Rules here follow the tax year 2025 guidelines, the newest the IRS has published as of 10 November 2026. Tax year 2026 guidelines were not posted yet. The IRS says the copy inside the Taxpayer Portal is the current one, so check it there before you file.

Fix the whole file at once

Drop in your blank IRIS template and your spreadsheet. Perfrow cleans every row, tells you which ones need you, and writes CSVs of at most 250 records. It runs in your browser, so names and TINs stay on your computer.

Open the 1099-NEC CSV fixer

Questions

Can I use a period in an IRIS CSV address?: No. Address lines may only contain letters, numbers, hyphens, slashes and spaces.
Is # allowed in a business name?: The formatting guidelines allow it, but Publication 5717 tells filers to remove hashtags from name and address lines. Removing it is the safe choice.

Sources (fetched 2026-11-10)

Other answers: All 54 columns · Required fields · Character limits · State codes · 250-record limit · Why files get rejected · Scientific notation · ZIP code format · Date format · Line breaks · Extra spaces · $0.00 cells · Y/N check boxes · Tax year · Error types · Headers do not match · From QuickBooks · TIN format · Key dates