What is the maximum foreign monetary gift amount not subject to taxation for US citizens?

You're on the right track with your understanding! For foreign gifts, there is indeed a reporting threshold of $100,000 (for 2023 tax year, adjusted to $104,000 for 2024) from a nonresident alien or foreign estate. If the total gifts from foreign persons exceed this amount, you need to report them on Form 3520. The good news is there is no maximum limit to how much you can receive as a gift - the IRS doesn't limit the amount. The more important point is that gifts, regardless of amount, are not subject to income tax for the recipient in the US. The reporting requirement is just that - a reporting requirement, not a tax. Form 3520 is fairly complex, and it's not available in most consumer tax software like TurboTax. Given the substantial amount you're receiving ($650,000), I'd strongly recommend working with a tax professional who has experience with international tax matters. The penalties for not filing or incorrectly filing Form 3520 are steep - potentially 5% of the gift amount per month, up to 25%.

After dealing with a similar foreign gift situation last year, I found an amazing service called taxr.ai (https://taxr.ai) that saved me so much stress. My uncle from Germany sent me a large sum, and I was totally confused about the reporting requirements until I tried their AI document analysis tool. I uploaded the bank statements and foreign gift documentation, and the system immediately identified it as a Form 3520 situation. It explained exactly what I needed to report and why, then gave me step-by-step guidance. They even have specialized features for foreign gift reporting that most regular tax software doesn't include. The best part was that it analyzed my specific situation rather than just giving generic advice. Might be worth checking out for your $650k gift situation!

I want to follow up about my experience with taxr.ai after I decided to try it despite my initial skepticism. I'm really glad I did! My situation involved a gift from my aunt in Barcelona, and I was completely lost about Form 3520 requirements. The platform analyzed my bank statements and the gift documentation, then provided incredibly detailed guidance. It identified exactly which sections of Form 3520 applied to my situation and explained the reasoning behind each requirement - much more thorough than the generic advice I was finding online. What impressed me most was the explanation of the filing timeline and potential penalties I could avoid by reporting correctly. For anyone dealing with foreign gifts, especially large ones like the $650k mentioned in this thread, it's definitely worth checking out. Saved me from what would have been a costly mistake!

If you're having trouble getting clear answers about Form 3520, you might want to talk directly with the IRS. I had a similar foreign gift situation last year and spent WEEKS trying to get through to them. After dozens of failed attempts, someone recommended Claimyr (https://claimyr.com) - it's a service that actually gets you through to a real IRS agent quickly. You can see how it works in this video: https://youtu.be/_kiP6q8DX5c I was super skeptical, but I was desperate after being on hold for hours multiple times. Somehow they got me connected to an IRS agent in about 20 minutes who answered all my foreign gift reporting questions. The agent confirmed exactly what I needed to do with Form 3520 and clarified the penalties for late filing. Made the whole process way less stressful, especially since I was dealing with a large gift amount like you are.

I want to admit I was completely wrong about Claimyr. After posting my skeptical comment, I was still desperate to talk to the IRS about my own foreign gift reporting questions, so I decided to try it anyway. I'm shocked to say it actually worked! After weeks of failing to get through the normal way, Claimyr got me connected to an IRS agent in about 25 minutes. The agent was super helpful and walked me through exactly what parts of Form 3520 applied to my situation, and confirmed I didn't need to pay any tax on the gift itself. For anyone dealing with this foreign gift situation, especially with large amounts like $650k, getting direct clarification from the IRS was incredibly valuable. They confirmed the $100,000 reporting threshold and explained exactly what supporting documentation I needed to keep. Completely worth it to avoid those massive penalties for incorrect filing!

Don't forget to consider your state tax implications too! While gifts aren't subject to federal income tax, some states have different rules. California (where you mentioned you live) follows the federal rules on this, so you should be good, but it's something to keep in mind. Also, make sure your son documents this properly on his end as well. Some countries have their own gift tax rules or limits on how much money can be transferred out. Thailand may have regulations about sending such large sums abroad. Lastly, be prepared for your bank to ask questions. A sudden $650,000 deposit will trigger reporting requirements for the bank, and they might freeze the funds temporarily while they verify the source.

I actually went through this exact situation last year with a $420,000 gift from my sister in Singapore. The most important thing to remember is there is NO TAX on the gift itself - just a reporting requirement. Form 3520 is definitely not DIY territory if you've never done it before. I tried using FreeTaxUSA and H&R Block software, but neither had good support for this form. I ended up paying an international tax specialist about $800 to handle everything. One thing nobody mentioned yet - make sure you also check if you need to file an FBAR (FinCEN Form 114) if you have signature authority or financial interest in foreign accounts. Different from Form 3520 but often applies to people with international connections.

As someone who works in tax compliance, I want to emphasize a few critical points that haven't been fully covered yet: First, timing matters significantly. You mentioned your son wants to transfer this next month - make sure he understands that large international transfers can take several days to process and may face additional scrutiny from both Thai and US banking authorities. Plan accordingly. Second, document EVERYTHING. Keep records of the relationship between you and your son, the gift letter, all transfer documentation, and any correspondence about the gift. The IRS may request this documentation years later during an audit. Third, consider the gift tax implications on your son's end in Thailand. While you won't owe US tax on receiving the gift, Thailand may have its own rules about large monetary gifts or transfers abroad that your son needs to comply with. Finally, given the substantial amount ($650,000), I'd strongly recommend getting a second opinion from another international tax professional even after you hire the first one. The peace of mind is worth the additional consultation fee when dealing with potential penalties that could reach tens of thousands of dollars for filing errors.

I want to add some perspective as someone who received a large foreign gift two years ago ($350k from my grandmother in the UK). The advice here is all solid, but I want to emphasize how important it is to get ahead of this process early. When I received my gift, I made the mistake of waiting until tax season to deal with Form 3520. By then, I was stressed and rushed, which led to some errors that required amendments. Start looking for that international tax professional NOW, not in March when everyone is swamped. Also, regarding your son in Thailand - have him get a letter from his bank confirming the source of the funds and that it's a legitimate transfer. Some US banks will want to see this to satisfy their anti-money laundering requirements. My UK bank provided something called a "source of funds declaration" that really helped smooth the process on the US side. One more thing - keep digital and physical copies of everything in multiple locations. I lost some paperwork in a computer crash and had to scramble to get duplicates from overseas, which was a nightmare. The IRS can ask for this documentation years later during audits, so treat it like you would any other important financial records. The good news is once you get through the reporting the first time, you'll know exactly what to expect if this ever happens again!