How do I handle a joint foreign account I share with my non-US spouse?

If you're a U.S. person and a joint owner of a foreign account, you report the entire maximum balance on your FBAR — not just your half. Joint ownership means each owner reports the full value, so a $40,000 joint account with your non-U.S. spouse counts as $40,000 toward your $10,000 threshold and is fully listed. If your spouse is also a U.S. person and you have only jointly held accounts, one of you can sometimes file a single FBAR covering both with a signed authorization; otherwise each U.S. person files separately. If your spouse is a nonresident alien with no U.S. filing duty, only you report, and you still report the full balance. The account being in another currency or in your spouse's home country doesn't change this. When in doubt, report the whole account and note the joint ownership.