EIN for Icelandic LLC Owners: The US Tax Treaty You've Been Told Doesn't Exist

Three things before you apply. First, your LLC needs state approval -- applying before formation is complete is a common, avoidable delay. Second, keep your Icelandic kennitala or passport accessible in case the IRS requests identity verification during a fax or phone follow-up. Third, settle on a mailing address for the CP 575 confirmation letter -- an Icelandic home address works, though many founders use a US virtual mailbox for faster, trackable delivery. Worth deciding early: whether the LLC's default disregarded-entity status suits your personal tax planning, given the rate comparison covered further down.

The application process itself does not vary by country. Icelandic founders use the same three non-resident routes as everyone else, since the IRS's online EIN system requires an SSN, ITIN, or US legal residence most applicants do not have. Fax is the most reliable method: complete Form SS-4 and send it to 855-215-1627 if faxing from within the US, or 304-707-9471 from outside -- i.e., from Iceland -- with real-world turnaround commonly running one to two weeks despite the IRS's official four-business-day target. Phone, at 267-941-1099, is open to international applicants Monday through Friday, 6:00 AM to 11:00 PM US Eastern Time; Iceland runs four to five hours ahead of Eastern depending on the season, leaving a comfortable calling window through the Icelandic afternoon and evening. Mail, at four to five weeks, is the slowest option and rarely worth choosing over fax.

A few fields on Form SS-4 consistently cause delays for non-resident applicants generally, Icelandic founders included. Line 7b asks for the responsible party's SSN, ITIN, or EIN -- if you have none of these, the IRS's own instructions say to write Foreign or N/A, not leave the field blank, since a blank Line 7b is one of the most common reasons non-resident applications bounce back for correction. Lines 4a-4b need your full Icelandic mailing address spelled out with Iceland written in full, since that is where your EIN confirmation letter, Form CP 575, will be mailed if you apply by post. Line 9a asks about entity classification -- accepting the default disregarded-entity status is standard for most single-member LLCs and does not affect whether Iceland's CFC rules apply, since that test looks at the jurisdiction where the LLC is formed, not the US tax election.

Once issued, your EIN arrives with a confirmation letter, Form CP 575, sent by fax, mail, or both depending on your application method -- keep it permanently, since banks and payment processors will ask for it during account opening. A lost CP 575 cannot be reissued, but the IRS will provide an EIN Verification Letter, Form 147C, as a substitute for any future banking or tax need. From here, most Icelandic founders move on to opening a US bank account -- Mercury and Relay both work for Iceland-based founders, since Iceland is not on either provider's restricted list -- and, since almost every non-resident-owned single-member LLC counts as a foreign-owned disregarded entity, filing Form 5472 alongside a pro forma Form 1120 annually, regardless of whether the LLC had US activity that year. The $25,000 minimum penalty for missing that filing applies independently of anything Iceland's Skatturinn separately requires.

If a formation service is handling your EIN application, confirm that the responsible party listed on Line 7a is you, the actual owner -- not a staff member at the formation company. The IRS defines the responsible party as whoever ultimately owns or controls the entity's funds and decisions, identified by their real name and passport-based nationality. An EIN record that lists someone other than the actual owner creates a mismatch that can complicate matters later if a bank or payment processor needs to verify beneficial ownership, which is the same information reported separately under BOI/FinCEN rules. If a provider suggests listing anyone but you, treat it as a red flag rather than a convenience, regardless of how routine it sounds.

Iceland's CFC rules, under Article 57a of the Income Tax Act, attribute a foreign company's undistributed profit to its Icelandic owner in proportion to their ownership, but only when the company is domiciled in a jurisdiction Iceland classifies as low-tax. That classification applies when the jurisdiction's corporate income tax rate is less than two-thirds of Iceland's own 20% rate -- a threshold of roughly 13.3%. The US federal corporate tax rate of 21% clears that bar comfortably, which means a US LLC does not fall into the low-tax jurisdiction category these rules were built to target. This mirrors a mechanism covered for a couple of other countries in this series, though Iceland reaches the same practical outcome through its own two-thirds test rather than a published blacklist. In practical terms, most single-member US LLCs owned by Icelandic residents sit outside Iceland's CFC accrual regime on the jurisdiction test alone, though a founder should confirm this with an Icelandic tax advisor rather than treat it as an absolute guarantee, since the rules have been under periodic review. Iceland's own tax authority, Skatturinn, publishes its CFC guidance and rate thresholds directly, and since Article 57a has been reviewed and amended before in response to evolving international standards, a founder should check Skatturinn's current published position rather than treating any single explainer as permanent.

Even with CFC accrual generally not applying, the practical tax outcome still depends on how the LLC's profits eventually reach you personally. Iceland taxes individual income progressively, combining a state rate that rises from 16.55% to 31.35% with a municipal rate averaging around 14.94%, which together can push the combined marginal rate above 46% at higher income levels -- notably higher than the flat rates a disregarded LLC's profits might otherwise suggest. This is worth modeling carefully with an accountant rather than assuming the US side of the picture is the only rate that matters: a founder who takes substantial personal income from the LLC in Iceland may find the Icelandic personal rate, not the US federal rate, is what actually drives their overall tax bill, treaty relief for double taxation notwithstanding. Iceland's own corporate tax rate of 20% is worth keeping in mind as a reference point too: if a founder ever considered electing corporate tax treatment for the LLC under Form 8832, the practical comparison is not simply Iceland versus the US, but Iceland's 20% flat corporate rate against its own personal rates that can run more than twice as high -- a genuinely different calculation than the one covered for founders in countries with lower top personal rates. Iceland's personal tax credit, the personuafslattur, reduces the tax owed on the first slice of income each month and is worth factoring into any comparison, since it effectively creates a tax-free floor before the progressive rates above start to bite -- meaningful for a founder in the early stages of a modest LLC, though it makes less difference once income grows past that initial band.

A few mistakes show up repeatedly. Assuming no US-Iceland tax treaty exists based on older material written during the 2000-2008 gap between the old and new treaties, when a valid treaty has been in force since December 2008. Assuming Iceland's CFC rules automatically apply to a US LLC, when the two-thirds-of-Iceland's-rate jurisdiction test generally excludes it given the US federal corporate rate. Focusing only on US-side tax rates when planning, when Iceland's combined personal income tax can exceed 46% at higher income levels and often drives the real overall tax outcome. Assuming the Icelandic kennitala process works identically to Form SS-4, when they are entirely separate systems serving different governments. And, as with every non-resident applicant regardless of country, leaving Line 7b of Form SS-4 blank instead of writing Foreign, which remains one of the most frequent reasons the IRS returns a non-resident application for correction.

A surprising number of guides claim there is no tax treaty between the United States and Iceland, and the confusion has a real historical root: the original 1975 treaty was terminated as part of renegotiation talks that began in 2000, creating a genuine gap for several years while a replacement was worked out. That replacement, however, was signed on October 23, 2007, ratified by the Senate in September 2008, and entered into force on December 15, 2008 -- and it remains in force today. An Icelandic founder relying on older material, or on a guide written during that gap years ago, may be planning around double-taxation exposure that a current, valid treaty already addresses. The treaty covers the taxation of business and personal service income and provides the standard mechanisms -- credits and exemptions -- for avoiding double taxation on the same income. None of this changes what Form SS-4 asks for -- the IRS has no field for treaty status -- but it is worth confirming which era of guidance you are reading before assuming Iceland lacks the protection most other countries in this series have. It is worth noting why the gap happened in the first place: the original 1975 treaty had grown outdated relative to both countries' modern tax law and had reportedly been used by third-country investors to obtain treaty benefits it was never designed to provide, which is part of why the replacement treaty added stronger anti-abuse provisions -- a detail that matters mainly for larger structures, not a typical single-member LLC, but worth knowing if a formation service or advisor mentions limitation-on-benefits requirements.