5 EIN Rules That Actually Cost Small Businesses Money

Written & reviewed by Ram Singh, founder, Numerawise Solutions · Last reviewed August 27, 2026

EIN basics: what it is, how to get one, when you need it, and common pitfalls for US small businesses.

An EIN is free, and the IRS issues it in minutes. Almost none of the cost of an EIN is in getting one — it is in the five rules that apply after you have it. Those rules decide whether your payroll filings land on the right account, whether IRS notices reach the right person, and whether restructuring your business quietly orphans the number your bank and your payroll provider already have on file. Here are the five, each checked against IRS documentation rather than the secondary guides that repeat each other.

1. It is free — and the application window is not open 24 hours

The IRS is blunt about the fee: “You never have to pay a fee for an EIN,” and it adds a warning to “beware of websites that charge for an EIN.” Paid filing services are selling you a form you can complete yourself in about ten minutes.

What trips people up is availability. The online application is not a 24/7 service. As the IRS currently publishes the hours (Eastern Time): Monday to Friday 6:00 a.m. to 1:00 a.m. the following day; Saturday 6:00 a.m. to 9:00 p.m.; Sunday 6:00 p.m. to midnight. Two further constraints matter more than the hours: you must complete the application in one session and cannot save it for later, and the session “expires after 15 minutes of inactivity, and you’ll need to start over.” Have the legal name, formation state, formation date, the responsible party’s SSN or ITIN, and your expected employment start date in front of you before you begin.

If you are outside the United States with no US legal residence or principal office, the online route is closed to you entirely. International applicants call 267-941-1099 — not a toll-free number — Monday to Friday, 6:00 a.m. to 11:00 p.m. Eastern. Fax and mail still work for everyone: the IRS’s own processing-status page, updated at the end of August 2026, now gives 9 business days for fax and 30 days for paper. Those figures are longer than the ones printed in the Form SS-4 instructions; the processing page is the newer source, so plan against it.

2. One EIN per responsible party per day

The IRS issues “only 1 EIN per responsible party per day.” This is the rule that ambushes anyone standing up a structure rather than a single company — a holding company with three operating subsidiaries, a property investor forming an LLC per building, a franchisee opening four locations as separate entities. If the same individual is named as responsible party on all of them, that is four calendar days of applications, not one afternoon.

The limit follows the responsible party, not the application channel, so switching from online to fax does not reset it. Sequence the applications around whichever entity needs to open a bank account or run payroll first, and build the extra days into your formation timeline rather than discovering them on the day.

3. The responsible party is a person — and you have 60 days to report a change

Since the IRS began enforcing this in May 2019, the responsible party “must be an individual (that is, a natural person), not an entity,” with a narrow exception for government entities. You cannot name your parent LLC. You cannot name your attorney or accountant as a placeholder either: the IRS states plainly that “nominees can’t apply for an EIN and shouldn’t be listed on Form SS-4.”

Now the part almost everyone skips. When the responsible party changes — a partner exits, a founder sells, a manager is replaced — you must report it on Form 8822-B within 60 days, under Regulations section 301.6109-1(d)(2)(ii). And here is exactly why it gets skipped: the form itself says “you will not be subject to penalties for failure to file this form.”

No penalty is not the same as no cost. The IRS sends deficiency and collection notices to the responsible party on record. If that person left two years ago, the notices go to them, you never see them, and — in the IRS’s own words — “penalties and interest will continue to accrue” on a matter you do not know exists. The 60-day form is free and one page. It prevents the most avoidable category of IRS surprise we see in cleanup work.

4. Most changes do not need a new EIN. Two common ones do

The instinct after any corporate change is to apply for a fresh number. Usually that is wrong, and a second EIN for the same business creates two open accounts, payroll history split across both, and a reconciliation problem that surfaces at year end. Per the IRS’s current guidance you do not need a new EIN when you:

• change your business name, or add a DBA or trade name;
• change your business location, or add locations;
• convert a partnership to an LLC that is still classified as a partnership;
• change your tax election to a corporation or an S corporation, where the entity already has its own EIN;
• are a corporation or a partnership and you declare bankruptcy.

You do need a new EIN when a sole proprietorship incorporates, and when a sole proprietor declares bankruptcy.

That bankruptcy line is worth reading twice, because it is the fact most often stated wrongly elsewhere. Bankruptcy is entity-dependent: a sole proprietor filing bankruptcy needs a new EIN; a corporation or partnership filing bankruptcy does not. Blanket statements that “bankruptcy requires a new EIN” are wrong for the majority of filers.

One more trap, on the S-corp line. The no-new-EIN safe harbour for a single-member LLC assumes the LLC has its own EIN. If the LLC has been operating on the owner’s sole-proprietor EIN, the IRS’s condition is that you do not elect corporate or S-corporation taxation and do not have employees or owe excise tax. Making the S election from that posture falls outside the safe harbour. Check which number is actually printed on your payroll filings before you elect, not after.

5. You cannot cancel an EIN. You deactivate the account

The IRS updated this page and the wording changed with it: “we can’t cancel it, but we can deactivate it.” Once assigned, the number becomes that entity’s permanent federal taxpayer ID number and is not recycled to anyone else. Before the account can be closed you must file all outstanding tax returns and pay taxes owed — so closing a business is a filing exercise first and a letter second.

Related, and genuinely new: as of August 2026 the IRS makes a digital CP575 downloadable in Business Tax Account, and says it serves as a substitute for the original CP575 notice series and Letter 147C. If you have ever waited on hold for a 147C letter because a bank or a payroll provider wanted EIN confirmation you could not find, that wait is now avoidable.

The single-member LLC question, answered properly

A single-member LLC treated as a disregarded entity, with no employees and no excise tax liability, does not need its own EIN — it “should use the name and TIN of the single member owner.” But the LLC is treated as a separate entity for employment taxes (wages paid on or after 1 January 2009) and for certain excise taxes (accruing on or after 1 January 2008), and in those cases it is required to use its own name and employer identification number. The IRS also notes that most new single-member LLCs classified as disregarded entities will need one anyway.

In practice: get the EIN when you form the LLC. It costs nothing, it takes ten minutes, and it prevents the messiest version of this problem, which is a year of payroll filed under a personal Social Security number.

Where this actually goes wrong in the books

Three patterns account for nearly every EIN problem that reaches us during a bookkeeping cleanup or a QuickBooks conversion:

1. Two EINs for one business. Someone applied again after a name change or an S election. Both accounts are live, filings are split across them, and the mismatch surfaces when a return is rejected or a notice arrives for an entity nobody in the office recognises.
2. Payroll filed under the wrong number. Usually a single-member LLC running payroll on the owner’s sole-proprietor EIN, or an entity that reorganised and never repointed the payroll provider. Correcting a year of Forms 941 costs far more than the ten minutes the original application would have taken.
3. A stale responsible party. No Form 8822-B was filed, so IRS correspondence goes to a former partner’s address. This one is invisible right up until it is expensive.

If you are not certain which EIN your filings actually use, pull the number from your most recent Form 941 and from your state registration and compare both to what your accounting file says. When they disagree, fix that before you reconcile anything else — every downstream number depends on it.

One document to stop citing

IRS Publication 1635 is still linked from live IRS pages, but its current revision dates from February 2014. It predates the natural-person responsible-party requirement and the 60-day Form 8822-B rule, it references the discontinued domestic EIN phone line, and it prints an international fax number that no longer matches the Form SS-4 instructions. If an article you are reading matches Pub 1635, it is quoting a twelve-year-old document.