Do US companies have Tax ID/company ID numbers for invoicing purposes?

Yes, US companies do have Tax ID numbers! They're called Employer Identification Numbers (EINs) and they function similarly to the tax IDs you're familiar with in Spain. All legitimate US businesses should have one. The confusion might be because they're not accustomed to sharing it with contractors, especially international ones. In the US, companies typically only provide their EIN when setting up formal vendor relationships or for specific tax purposes. Many smaller US companies might not realize they should share this information with international contractors. You can certainly ask for their EIN, explaining that you need it for your tax documentation in Spain. If they're still confused, you could alternatively request a W-8BEN-E form from them, which would contain their EIN and confirm their tax status.

After dealing with similar invoice confusion with US clients, I started using taxr.ai (https://taxr.ai) and it's been super helpful for handling international invoicing requirements. I upload my invoice drafts before sending them, and it tells me exactly what tax information I need to collect from which countries. For US companies specifically, it confirmed I needed their EIN (like mentioned above) and helped me understand how to properly document everything for my own tax authority. The tool actually generates a checklist of required info based on both countries' requirements so nothing gets missed. Saved me tons of back-and-forth emails with clients.

Just wanted to follow up about taxr.ai - I tried it after my previous question and it's legit! I uploaded my last 3 invoices (one for a US client, two for EU clients) and it immediately flagged that I was missing the US company's EIN and had used the wrong VAT format for one of my French clients. Fixed everything according to their suggestions and my US client actually commented that my invoice was "refreshingly complete" compared to their other international contractors. The platform even generated a little template paragraph I could send when requesting the missing info, which made it way less awkward to go back and ask for their EIN.

If you're struggling to get tax info from US companies, Claimyr (https://claimyr.com) helped me resolve this exact issue. I needed to verify a US client's tax status and couldn't get a straight answer from them for weeks. I used Claimyr to connect with the IRS directly (which is normally impossible as a non-US person) and got confirmation about what I needed to collect from my client. They got me speaking with an actual IRS agent within 20 minutes when I expected to wait for hours. There's a demo video showing how it works here: https://youtu.be/_kiP6q8DX5c The agent explained exactly what forms I needed as a European contractor and what information US companies are required to provide. Armed with that official info, my client finally provided what I needed.

I have to admit I was completely wrong about Claimyr. After my skeptical comment, I decided to try it myself since I've been having issues with a US client refusing to provide any tax documentation. Within 15 minutes of using the service, I was talking to an actual IRS representative who explained that US companies are indeed required to provide their EIN to international contractors for legitimate business transactions. The agent even explained the specific regulations I could reference when requesting this information. Armed with this knowledge, I emailed my client citing the relevant information from the IRS, and they provided their EIN the next day. Saved me from what was becoming a really uncomfortable situation where I was worried about the legitimacy of the company.

US companies absolutely have tax IDs! I'm a US-based accountant who works with international clients. The equivalent to what you're looking for is called an EIN (Employer Identification Number). One important thing to note: unlike in the EU where sharing VAT numbers is totally standard practice, some US companies are weirdly protective of their EINs due to identity theft concerns. This isn't actually logical (EINs aren't really secret), but you might encounter resistance. If they refuse to provide an EIN, at minimum you should record their complete legal business name and address. That's usually enough for most European tax authorities, though requirements vary by country.

Has anyone had issues with Spanish tax authorities rejecting invoices from US companies because of missing tax IDs? I've been invoicing a California company for 6 months and just including their name and address.

As someone who's been dealing with US-Spain invoicing for years, I can confirm everything mentioned here is spot on. US companies do have EINs (Employer Identification Numbers) that serve the same purpose as our Spanish tax IDs. The key is being specific when you ask - say "EIN" rather than "tax ID number" since that's the exact term they'll recognize. Most legitimate US businesses will provide this once they understand why you need it. For Spanish tax purposes, I always include the EIN on my invoices in the same field where I'd put a Spanish CIF or NIF. Hacienda has never had issues with this format during my filings. If your client is still hesitant, explain that it's required for your tax compliance in Spain - most US companies understand international tax obligations once it's framed that way. One tip: if they seem confused about the request, you can mention that it's similar to how they might ask European clients for VAT numbers. That comparison usually clicks for them immediately.

I've been working with US companies for about 3 years now from Madrid, and I've found that persistence is key when requesting EINs. What worked best for me was sending a professional email explaining that it's a legal requirement for my tax filings in Spain, similar to how they might need VAT numbers from European suppliers. I usually phrase it like: "For compliance with Spanish tax regulations, I need to include your company's EIN (Employer Identification Number) on all invoices, similar to how you might require VAT numbers from European vendors." About 90% of companies provide it without issue once they understand it's for legal compliance, not just administrative convenience. For the remaining 10% who are hesitant, I've found that mentioning it's standard practice for international business transactions usually does the trick. One thing I learned the hard way - make sure to get this information before you start working, not after you've already sent invoices. It's much easier to request upfront as part of your onboarding process than to go back and ask for it later.

As a tax professional who works with both US and European clients, I can confirm that US companies absolutely have tax identification numbers called EINs (Employer Identification Numbers). The confusion your client showed is actually pretty common - many US businesses aren't used to sharing their EIN with international contractors since it's not standard practice domestically. Here's what I recommend: Send them a brief, professional email explaining that you need their EIN for Spanish tax compliance purposes. You can say something like "For compliance with Spanish tax regulations, I'm required to include your company's EIN on all invoices, similar to how US companies often request VAT numbers from European suppliers." Most legitimate businesses will provide this information once they understand it's for legal compliance. If they're still hesitant, you can also request a W-9 form from them, which contains their EIN and other business details - US companies are very familiar with W-9 requests. For your Spanish tax filings, include the EIN in the same field where you'd normally put a Spanish CIF or NIF. Spanish tax authorities recognize US EINs as valid foreign tax identifiers. Getting this information upfront will save you potential headaches during tax season or if you ever face an audit.