Installment one got you a legal entity — an LLC or corporation now on file with the New York Department of State, with a certificate to prove it. Installment two gets that entity a number. Not a nickname, not an internal file code — an Employer Identification Number, the nine digits the IRS uses to track your business as its own taxpayer, separate from you. Think of it as the business equivalent of your own Social Security number, except free, instant, and — unlike your SSN — something you'll hand out constantly: to your bank, your insurer, and nearly every government office that shows up later in this series.

The IRS's own trigger list for a required EIN reads narrower than most owners assume: hire an employee, operate as a partnership or corporation, or owe certain excise taxes, and you need one, full stop. A single-member LLC with no employees and no excise liability is technically the one structure the IRS lets skip it, filing instead under the owner's own Social Security number. In practice, that loophole rarely survives contact with a bank — the IRS's own guidance for single-member LLCs notes plenty of owners get one anyway just to open a business account, or because their state may require it. Every filing ahead in this series — workers' comp, DOB registrations, PASSPort vendor setup, M/WBE certification — is also built to ask for a federal tax ID belonging to the business, not the owner. If you formed a corporation or a multi-member LLC in installment one, the EIN isn't optional. If you formed a single-member LLC, it's optional on paper and close to mandatory in the field.

Sequencing matters, and the IRS says so directly: form your entity through the state first, then apply for the EIN. That means your Articles of Organization or Certificate of Incorporation needs to be filed and accepted by the New York Department of State — the step installment one walked through — before you sit down at the IRS's application. Apply too early, on an entity that doesn't legally exist yet, and you risk an application that doesn't match anything on record. Once your state filing is accepted, there's no reason to wait: the EIN application takes minutes, and nothing about it improves with age. Exactly how many days to leave between the two, and whether your specific paperwork needs a filed copy in hand first, is worth a two-minute check with your attorney or accountant rather than a guess — but the order itself, entity first, EIN second, is not in question.

The application lives at irs.gov, it's free, and for most NYC contractors it's the only method they'll ever need. The online EIN assistant is open to any domestic entity — organized in the U.S. or a U.S. territory, with its principal place of business here — as long as the person applying, what the IRS calls the "responsible party," has a Social Security number or an individual taxpayer ID number. The responsible party is whoever actually owns or controls the business — the IRS's own examples are a corporation's principal officer or a partnership's general partner. For an LLC, the practical read is the same: whoever's actually running the company. For a typical owner-operated NYC construction outfit, that's you, and you almost certainly qualify.

Finish the online application correctly and the IRS issues your EIN before you close the browser tab — the page's own language is "we'll issue your EIN immediately online." The catch is the same one that trips people up with plenty of instant-issue government tools: that confirmation letter appears once. The application page tells you to print it for your records, not "we'll email it to you later." Save it as a PDF, print a paper copy, put it in whatever folder is holding your Articles of Organization — because this is the document a bank teller, a bonding agent, or a city procurement portal is going to ask you to produce. The tool itself runs nearly around the clock — weekdays from 6 a.m. to 1 a.m. the next morning, Eastern time, with shorter windows on weekends — so there's little excuse to be doing this at the last minute.

Anyone who can't clear the SSN/ITIN requirement — most commonly a foreign national serving as responsible party for a U.S. entity — falls back to paper: Form SS-4, faxed or mailed to the IRS. Fax it with a return fax number included and the IRS sends your EIN back in about four business days; mail it to the IRS's EIN Operation in Cincinnati and budget roughly four weeks. For everyone else, online is faster, free, and finished before the paper version would even arrive.

On cost, the IRS is blunt about it: "You never have to pay a fee for an EIN." It's worth repeating because a search for "apply for EIN" surfaces a small industry of look-alike sites charging a fee to fill out the same free form on your behalf, some styled to resemble a government page. The real application only lives at irs.gov. If a site asks for a credit card before it hands you a tax ID number, close the tab.

The most common way this goes sideways is applying twice. The online tool caps you at one EIN per responsible party per day, which stops an accidental double-click mid-session — but nothing stops a distracted owner from running the application again a week later, having forgotten, or never having saved, the first confirmation letter. Each successful session issues a brand-new number; it doesn't check whether your entity already has one. The result is two federal tax IDs for one business, which is common enough that the IRS's own internal manual devotes a dedicated section to sorting it out after the fact. Cheaper to avoid it: before you apply, make sure you — or whoever set up the entity — hasn't already run this step.

If that ship has sailed and the confirmation letter is genuinely gone, don't start over. The IRS has been rolling out a digital version of that notice, accessible anytime through a business's online IRS account and accepted by banks as written confirmation of the EIN — worth checking first. If that's not available, the fallback is a call to the IRS Business & Specialty Tax Line at 800-829-4933 (weekdays, 7 a.m. to 7 p.m. local time) to ask about your EIN. Either way, the fix is a phone call or a login, not a new application.

The third mistake is quieter and shows up later: what you told the IRS on the EIN application doesn't match what you actually filed with the state. The application asks you to identify your entity type and legal name, and that answer feeds directly into how the IRS sets up your tax account — it is not a place to round off "LLC taxed as an S-corp" to just "corporation," or to type your business name differently than it appears on your Certificate of Incorporation. Catch it before you submit by holding your NY Department of State paperwork next to the application and matching them line for line. Catch it after the fact and the fix isn't self-service — the IRS's standard change-of-information form only covers a new address or a new responsible party, not a corrected entity type — so that call goes to the IRS directly, and it's a good one to loop your accountant into.

So, in order: confirm your LLC or corporation is actually on file and accepted by the state, have your responsible party's Social Security number or ITIN in hand, and set aside ten uninterrupted minutes at irs.gov — not a search-engine ad, not a site that wants a credit card. Apply, get your EIN on the spot, and save that confirmation letter in at least two places before you do anything else with it. That number is what turns your paper entity into a business your bank, your insurer, and the rest of this series will actually recognize.