The $10,000 threshold is the FBAR's front door, and the aggregation rule behind it is the single most misunderstood piece of the entire regime. Read the regulation carelessly and you conclude your four small accounts don't matter. Read it correctly and you realize the opposite. This page states the rule precisely, then works through the examples that decide real cases.
The rule, precisely
For each calendar year, you must file an FBAR if the aggregate value of all foreign financial accounts in which you hold a financial interest or have signature authority exceeded $10,000 at any time during the calendar year. Key elements:
- Aggregate, not per-account. Sum everything before testing the threshold.
- "At any time" — a single moment is enough. There is no averaging, no year-end test, no materiality grace period.
- Valued in US dollars at the exchange rates in effect when measured.
- Once the threshold is crossed, everything is reported — every qualifying account, even the $900 savings account that contributed almost nothing.
Worked examples
Example 1 — the aggregation trap. Ana has three accounts: €3,500, €3,000 and €2,800. At a 1.10 rate, that's $3,850 + $3,300 + $3,080 = $10,230 at the March peak. No single account ever reached $10,000. FBAR required for the year — all three accounts reported.
Example 2 — the passing wire. Ben's only foreign account holds the equivalent of $6,000 all year. In November, the proceeds of a property sale — $180,000 — sit in the account for four days before he wires them onward. FBAR required, and the maximum value reported for that account is the $180,000 peak, not $6,000.
Example 3 — currency drift. Carmen has held €9,000 in a German account for years, comfortably under $10,000 at the rate when she opened it. A weakening dollar pushes €9,000 to $10,400 in the spring. FBAR required — nothing changed in her banking, but the dollar moved.
Example 4 — signature authority aggregates too. Dan personally holds $4,000 abroad and has signature authority over his employer's $9,000 foreign operating account. Combined: $13,000. FBAR required, reporting both — his account under his financial interest, the employer account under signature authority, each with its own maximum value.
Example 5 — the near miss. Eve's combined peak is exactly $9,850 for the entire year. No FBAR. But she keeps the statements — because record-keeping for the years you don't file is how you prove you didn't owe.
What counts as an "account" for aggregation
Into the pot: bank accounts, savings accounts, checking accounts, brokerage accounts, mutual fund accounts, cash-value life insurance or annuity contracts issued by foreign insurers (in many structures), foreign pension arrangements that constitute financial accounts, prepaid cards linked to foreign accounts, and accounts held for your benefit by someone else (nominee arrangements).
Stayed out: directly held foreign real estate, shares of foreign companies held directly (though they may be Form 8938 assets), physical cash in a safe, and accounts at US institutions regardless of what they invest in.
Gray-zone assets — some foreign pensions, funds held at foreign exchanges for crypto trading — are exactly where professional judgment earns its fee. The conservative posture when genuinely uncertain is inclusion.
The details inside "maximum value"
Once reportable, each account is reported at its maximum value during the year, converted to dollars. For accounts denominated in foreign currency, Treasury's yearly exchange rate is the standard default, with the regulations permitting the rate on the day of the actual maximum for peak-value reporting. Your record-keeping file should show the rate and arithmetic for each account.
The unintentional-violation league table
In practice, the aggregation rule produces most of the world's non-willful FBAR violations:
- The multi-account expat who assumed $10,000 per account (Example 1)
- The currency drifter whose balances crossed in dollar terms (Example 3)
- The one-time wire through a small account (Example 2)
- The employee co-signer who never thought about the work account (Example 4)
- The joint-account holder who assumed "half" of a joint account counts as half
All five are the classic non-willful profile — and exactly the profile where reasonable cause documentation and prompt catch-up filing resolve matters with penalties waived in most cases. The exposure becomes serious only when the facts drift toward willfulness (see penalties).
Practical habit: one spreadsheet, ten minutes, every January
List every foreign account you can transact in or benefit from; enter each account's peak balance from statements as the year closes; convert at Treasury's rate; look at the total. If the total ever touches $10,001 — file. That habit is the entire compliance burden of the aggregation rule.
This page is general information, not tax or legal advice. See the IRS FBAR reference guide and 31 CFR 1010.350 for the controlling text.
Frequently asked questions
Is the FBAR $10,000 threshold per account or total?
Total. You aggregate the value of all foreign financial accounts you have a financial interest in or signature authority over. If the combined total exceeds $10,000 at any moment during the calendar year, every one of those accounts is reportable — including accounts worth far less than $10,000.
Does a temporary spike over $10,000 trigger FBAR reporting?
Yes. The test is whether the aggregate exceeded $10,000 at any time during the calendar year — even briefly. A wire that passed through your account for two days, or a currency swing that briefly pushed your combined balances over the line, creates the filing duty for that year.
Do currency fluctuations count toward the threshold?
Yes. Account values are measured in US dollars at the relevant exchange rates, so a weakening dollar can push stable foreign-currency balances over $10,000 without you moving a cent. This is one of the most common unintentional violations among long-term expats.
Do I include my spouse's separate accounts in the aggregation?
You aggregate accounts in which YOU have a financial interest or signature authority — your own accounts, your half-ownership of joint accounts (counted at full value once), and any account you can direct by signature. Your spouse's separate accounts are your spouse's aggregation, unless you have signature authority over them too.
Once over the threshold, what do I report?
Each and every foreign financial account for that year: institution name and address, account number, account type, joint-owner identification where applicable, and each account's maximum US-dollar value during the year.