A foreign bank account can create a major U.S. tax filing duty. The FBAR, or FinCEN Form 114, applies when qualifying foreign accounts exceed $10,000 combined at any time. U.S. citizens, residents, and certain entities may need to report them. For 2026, a non-willful FBAR violation can reach $16,536. Willful violations can reach $165,353 or 50% of the account balance.