Key takeaways
- The IRS does not apostille its own documents. Form 6166, the US Tax Residency Certificate, is apostilled by the US Department of State in Washington, DC, while the EIN confirmation letter and 147C reissue can be apostilled by either the US Department of State or a state Secretary of State (SOS) after a notarized true-copy certification.
- Form 6166 is obtained by filing Form 8802, which has an IRS user fee of $85 for individual applicants or $185 for non-individual applicants including LLCs taxed as partnerships or corporations (verify on irs.gov/forms-pubs/about-form-8802), and a typical 6-to-10-week IRS processing window before Form 6166 is mailed. The receiving address on Form 8802 is the address the IRS uses to mail the certificate, so the address chain has to be correct before the application is filed.
- Multi-state LLCs that form in Delaware but operate from another city typically have Form 6166 apostilled in Washington, DC, as a federal document, and the Certificate of Good Standing apostilled in the state of formation; the two apostilles often travel together to the receiving bank.
Before you start
- Confirm the LLC has a valid EIN and the EIN confirmation letter (CP575 from the original assignment or 147C as the IRS-issued replacement) is in hand.
- Identify the receiving country and confirm whether it is a member of the Hague Apostille Convention; non-member countries require consular legalization, which is a separate and longer process.
Who this is for
- Foreign founders forming a US LLC remotely who need to open a foreign-currency account in their home country.
- Multi-state LLC operators who need to apostille both Form 6166 and a Certificate of Good Standing for international banking or tax treaty filings.
- US-formed LLCs with foreign members who need apostilled tax documentation for K-1 partnership distributions, Foreign Investment in Real Property Tax Act (FIRPTA) withholding, or treaty benefit claims at a foreign tax authority.
Foreign banks and overseas tax authorities often ask for an apostilled IRS document. The IRS does not apostille its own paperwork. The US Department of State handles Form 6166, the US Tax Residency Certificate, and the state Secretary of State handles the EIN confirmation letter after a notarized true-copy.
Which IRS documents can be apostilled, and by whom
Not every IRS document follows the same apostille path. The US Department of State (specifically the Office of Authentications in Washington, DC) handles federal documents and IRS-issued original certificates. State Secretaries of State handle documents that have been notarized in their state, which is the usual path for the EIN confirmation letter (CP575 or 147C) after a US notary public produces a notarized true-copy.
The Hague Apostille Convention covers documents going to member countries; documents going to non-member countries require a longer consular legalization process through the embassy of the receiving country. The Hague membership list expanded on 2023-11-07 when the People's Republic of China became a Convention member, which simplified the path for documents destined for Mainland China.
| IRS document | Apostille authority | Notarization needed? | Typical use |
|---|---|---|---|
| Form 6166 (US Tax Residency Certificate) | US Department of State, Office of Authentications, Washington, DC | No (IRS-issued original) | Tax treaty benefit claim at foreign tax authority |
| EIN confirmation letter (CP575) | State Secretary of State (after notarized true-copy) | Yes (notarized true-copy) | Foreign bank account opening |
| 147C (EIN verification reissue) | State Secretary of State (after notarized true-copy) or US Department of State | Yes (notarized true-copy) for state path | Foreign bank account opening when CP575 is lost |
| Form 1065 / Form 1120 signed copy | State Secretary of State (after notarized true-copy) | Yes (notarized true-copy) | Foreign partner K-1 distribution, foreign-owned single-member LLC Form 1120 + 5472 filing, or treaty claim |
| Form 4506 transcript with IRS embossed seal | US Department of State, Washington, DC | No (IRS-issued original) | Foreign tax authority transcript request |
Which IRS document goes to which apostille authority. The choice depends on whether the document is IRS-issued (federal authentication path) or a notarized true-copy (state authentication path).
Hague Apostille Convention 2026 status
The People's Republic of China joined the Hague Apostille Convention on 2023-11-07, simplifying the path for documents destined for Mainland China. Documents going to Hong Kong and Macau followed an apostille path before that date as separate jurisdictions. Canada joined the Convention on 2024-01-11 and Saudi Arabia joined on 2022-12-07, so documents to those countries now use the apostille path. A short list of commercially relevant non-Hague countries remains, including the United Arab Emirates, Iraq, Jordan, and Vietnam; verify current status at hcch.net/en/instruments/conventions/status-table/?cid=41 before filing. Non-Hague countries require consular legalization through the receiving country's US embassy.
Form 6166 versus Certificate of Good Standing: two apostilles for different audiences
Foreign banks and foreign tax authorities sometimes ask for both Form 6166 and a Certificate of Good Standing (CGS) at the same time. The two documents prove different things and travel through different apostille authorities. Form 6166 confirms the entity's US tax residency for treaty purposes; the CGS confirms the entity is in good standing with its formation state's SOS office. The Certificate of Good Standing 10-state guide covers the state-by-state CGS apostille process.
The two documents typically travel together to the receiving bank. The Form 6166 apostille is issued by the US Department of State in Washington, DC; the CGS apostille is issued by the formation state's Secretary of State. A Delaware LLC opening a foreign account, for example, would request Form 6166 from the IRS (apostilled in DC) and the CGS from the Delaware Secretary of State (apostilled in Delaware), then send both apostilled documents to the foreign receiving bank.
When the receiving bank asks for only one document
If the receiving bank's know-your-customer (KYC) checklist only mentions one apostilled document, ask which one. Some banks accept the CGS alone for entity verification; others insist on Form 6166 for tax treaty filings. The two documents prove different facts, so the bank's choice depends on the purpose of the account and the bank's internal compliance rules.
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The Form 8802 application: user fee and the 6-to-10-week timeline
Form 6166 is not requested directly; it is the certificate that issues after the IRS approves Form 8802 (Application for U.S. Residency Certification). Form 8802 has an IRS user fee of $85 per application for individual applicants or $185 per application for non-individual applicants, which includes LLCs taxed as partnerships or corporations (verify the current fees on irs.gov/forms-pubs/about-form-8802 before filing). The typical IRS processing window is 6 to 10 weeks before Form 6166 is mailed, with peak-season delays sometimes longer. Expedited processing is not generally available, so the timeline matters when a foreign bank or tax authority has a deadline.
The mailing address on Form 8802 is the address the IRS uses to mail Form 6166. The address chain has to be correct before the application is filed: the address should match the EIN confirmation letter, the address on the bank account opening packet (if already opened), and the address the apostille authority will see on the returned envelope. A mismatched address can cause Form 6166 to be returned to the IRS, which restarts the timeline.
- 1File Form 8802 with the IRS by mail or by fax depending on the applicant type; include the user fee payment ($85 for individual applicants, $185 for non-individual applicants).
- 2Wait 6 to 10 weeks for IRS processing; longer during peak filing seasons.
- 3Form 6166 mails to the address listed on Form 8802; the envelope arrives with the IRS embossed seal.
- 4Send Form 6166 to the US Department of State Office of Authentications for the apostille; the federal fee is $20 per document with a typical 10-to-12 business day mail processing window (verify on travel.state.gov).
- 5The apostilled Form 6166 returns to the address listed on the apostille request; forward to the foreign receiving bank or tax authority.
Form 8802 receiving address is a single point of failure
If the address on Form 8802 fails to receive the Form 6166 envelope, the IRS marks the document as returned and the applicant has to refile or follow up through the Practitioner Priority Service. Running the address through the Address Checker before filing confirms USPS Delivery Point Validation and reduces the risk of a returned envelope.
DE / FL / NY State Department apostille fees and expedited processing
State Secretaries of State handle the apostille for documents that have been notarized in their state, which is the path for the EIN confirmation letter (CP575 or 147C) after a US notary produces a notarized true-copy. The fees and processing windows vary state by state. Delaware, Florida, and New York are three of the most common states for foreign founder LLC formation, and each handles apostille requests through a different office and at a different fee.
Expedited processing is generally available in all three states for an additional fee. Mailing time on top of processing time can add 1 to 2 weeks, so the total elapsed time from notarization to apostilled document in hand is typically 2 to 4 weeks for standard processing and 1 to 2 weeks for expedited. Verify current fees and processing windows on each state's Secretary of State website before mailing, since the fee schedules change periodically.
| State | Apostille office | Standard fee (verify current) | Typical processing |
|---|---|---|---|
| Delaware | Delaware Department of State, Division of Corporations | $30 per document (verify on corp.delaware.gov) | Standard 1-2 business days plus mailing; expedited same-day available |
| Florida | Florida Department of State, Division of Corporations | $10 per document (verify on dos.fl.gov/sunbiz; $20 surcharge applies to Florida Clerk of Court certifications) | Standard 5-7 business days plus mailing; expedited 1-2 business days available |
| New York | New York Department of State, Division of Licensing | $10 per document (verify on dos.ny.gov) | Standard 1-2 weeks plus mailing; in-person same-day available at the Albany or NYC office |
Apostille fees and processing windows for the three most common foreign founder LLC formation states. Fees and timelines change periodically; verify on each state's Secretary of State website before mailing.
Multi-city LLC: which state SOS handles your apostille
Multi-state LLCs often form in one state (commonly Delaware for the favorable LLC Act) and operate from another (often Florida for the no-state-income-tax climate, or California for proximity to capital and customers). The question for apostille is not where the LLC operates; it is where the document was notarized.
An EIN confirmation letter notarized by a Florida notary is apostilled by the Florida Secretary of State, even if the LLC is formed in Delaware. The notarization location, not the LLC's formation state, determines the apostille authority for state-handled documents. Form 6166, by contrast, is always apostilled in Washington, DC because it is a federal document.
- EIN letter notarized in Florida → Florida SOS apostille (regardless of LLC formation state).
- Operating agreement notarized in California → California SOS apostille.
- Form 6166 → US Department of State, Washington, DC (federal document, no notarization required).
- Certificate of Good Standing → formation state SOS apostille (the SOS that issued the CGS handles the apostille).
- Form 1065 signed copy notarized in Delaware → Delaware SOS apostille.
Common rejection reasons and how to avoid them
Apostille requests fail for predictable reasons: the underlying notarization is defective, the document is a photocopy not a true-copy, the notary's commission has expired, the state SOS does not recognize the notary's signature, or the document is not eligible for apostille. Most rejections come back with a written explanation and a refund of the unused portion of the fee. Refiling typically takes a second 1-to-2-week processing cycle.
- Notary commission expired at the time of notarization, which is fatal to the apostille.
- Notarized true-copy missing the notary's stamp and signature on the actual document (not just the notary block).
- Wrong state SOS handling the request: the notarization is from one state and the request goes to another state.
- Document is a photocopy without a notarized true-copy certification.
- Form 8802 receiving address fails to receive Form 6166, which causes a return-to-sender at the IRS step.
- Receiving country is not a Hague Convention member; the request needed consular legalization instead.
Pre-validate the receiving address before filing
Running the receiving address through the Address Checker returns the USPS Delivery Point Validation result and the commercial mail receiving classification. The check takes about 30 seconds and avoids the most common rejection cause for Form 8802 (Form 6166 returned to the IRS due to undeliverable address).
How save office fits the IRS letter and apostille flow
save office operates real US business addresses in seven cities, including Wilmington Delaware for the formation state apostille path and Tampa Florida for the no-state-income-tax operating address. The address is accepted on Form 8802 as the receiving address for Form 6166, on the EIN confirmation letter for the notarized true-copy apostille, and on the bank account opening packet for the foreign receiving institution.
Foreign founders with a multi-state LLC benefit from the multi-city flexibility: the formation state SOS handles the CGS apostille while the operating state SOS handles the EIN letter apostille. The Address Checker tool runs USPS Delivery Point Validation on the Form 8802 receiving address before filing, which avoids the most common cause of a returned Form 6166 envelope. The get-started flow handles the documentation in 24 hours so the address is ready before the apostille chain begins.
Frequently Asked Questions
