Short answer: Deposit market share is a bank's deposits in a county divided by all the deposits at FDIC-insured offices in that county. The numbers come from the FDIC's Summary of Deposits, a count of deposits at every branch taken once a year as of June 30. The 2026 survey covers $19.05 trillion at 75,859 offices of 4,249 institutions in 3,195 counties. Three things decide whether a share means what it appears to mean: deposits are counted where they are booked and not where the customer lives, credit unions are not in the survey, and a share can rise because a bank bought another bank and not because it won customers.
What the survey is
The Summary of Deposits is the FDIC's annual survey of branch office deposits. Every FDIC-insured institution is in it, including insured US branches of foreign banks, and each one reports the deposits held at each of its offices as of June 30. The FDIC publishes the results in the early fall. It is the source behind the FDIC's own deposit market share reports and the starting point when regulators look at the competitive effect of a bank merger.
It is the only public data that puts a bank's deposits in a place. A call report gives one deposit total for the whole bank. The Summary of Deposits splits that total across offices, which is what lets anyone say how much a bank holds in a particular county.
How the share is calculated
Add up the deposits at all of a bank's offices in a county, and divide by the deposits at every FDIC-insured office in that county. A bank with $300 million in a county where all offices together hold $2 billion has a 15% share. Rank the banks by share and you have the county's league table.
The county is the usual unit because it is the one the data supports cleanly, and it is how most bankers and most public reports state a share. It is not always the market. Regulators analyze competition in banking markets that the Federal Reserve Banks define, and those often take in several counties or only part of one.
Seven surveys: fewer banks, fewer offices, more deposits
One survey gives a share. A run of them shows whether the share is moving, and what the ground under it is doing. Here are the national totals for each survey from 2020 to 2026.
| Survey, as of June 30 | Institutions | Offices | Deposits |
|---|---|---|---|
| 2020 | 5,076 | 84,982 | $15.59 trillion |
| 2021 | 4,960 | 81,791 | $17.24 trillion |
| 2022 | 4,781 | 79,172 | $18.14 trillion |
| 2023 | 4,655 | 77,770 | $17.27 trillion |
| 2024 | 4,548 | 76,727 | $17.41 trillion |
| 2025 | 4,431 | 76,097 | $18.10 trillion |
| 2026 | 4,249 | 75,859 | $19.05 trillion |
Source: BankingLENS, from the FDIC Summary of Deposits for each year. Every year is built by the same code as the latest one. Deposits are those at the domestic offices of FDIC-insured institutions, including insured branches of foreign banks.
From 2020 to 2026 the country lost 9,123 bank offices, about one in nine, and 827 institutions, about one in six, while deposits grew 22%. The only year deposits fell was 2023, by 4.8%. The 2026 survey shows deposits up 5.2% on 2025, a third straight year of growth, with 182 fewer institutions and 238 fewer offices.
That backdrop matters when you read your own share. If the county's total grew 5% and your deposits grew 3%, you gained customers and lost share. If a competitor closed two offices and its deposits moved to the branch in the next county, your share rose without anything changing at your bank.
Trap one: deposits are counted where they are booked
The survey assigns a deposit to the office that books it, not to the place the customer lives. Large banks book internet, card, trust and brokered deposits at a single address, so one office can hold more money than the county around it could plausibly supply.
The 2026 survey shows $479 billion of deposits in Minnehaha County, South Dakota, the county that holds Sioux Falls, across 83 offices of 26 institutions. One office holds 96% of it. New Castle County, Delaware, which holds Wilmington, shows $472 billion, with 66% in one office. Salt Lake County, Utah shows $1.18 trillion, about 6% of every deposit dollar in the survey, spread across 57 institutions.
In BankingLENS a county is labeled a booking-office county when one office holds at least 60% of the county's deposits and at least $1 billion. The 2026 survey has 25 of them. Nothing is removed from the totals, because the result would no longer match the FDIC's published figure, which is the number a banker will check against. The share is shown and the caveat is shown with it. Salt Lake County is not one of the 25, because several large booking offices share it, which is a reminder that the label is a floor and not a complete list.
The same effect exists at smaller scale. A community bank that books all of its online accounts, or all of its brokered certificates, at the main office will show a larger share in its home county than its local customers account for.
Trap two: credit unions are not in it
The survey covers FDIC-insured institutions, and credit unions are insured by NCUA instead. A bank's deposit market share is therefore its share of bank deposits, not of all the deposits in the county. Credit unions report one deposit total for the whole institution and not one for each branch, so putting them into a county takes an estimate. We cover how large the gap is, and how we estimate it, in do credit unions count in deposit market share?
Trap three: growth that was bought
When a bank acquires another, the acquired deposits appear in the survey after the deal closes, as a jump. A share that rose from 8% to 14% in one year may describe a bank that out-competed everyone or a bank that wrote a check, and the share alone cannot tell you which.
The survey does make the difference recoverable. The FDIC gives every office a number that stays with the office when it changes owners. Between two surveys, each office either kept its owner, changed owner, opened or closed, so the deposits a bank gained by buying offices can be separated from the growth at the offices it already had. A deposit trend that does not make that split overstates every acquirer.
Trap four: one day a year
June 30 is a single day, and a quarter-end at that. Public funds, tax receipts and a large commercial customer's balance can all sit in an office on that date and be gone in August. A one-year move in a small county is often one depositor. Read the direction over several surveys before reading anything into one.
Concentration, in one number
The Herfindahl-Hirschman Index, or HHI, turns a county's league table into a single measure of concentration. Square each institution's share, in percentage points, and add the squares. A county with one bank scores 10,000. A county with four banks at 40%, 30%, 20% and 10% scores 3,000.
Its main use is screening mergers. If the banks with 20% and 10% combine, the index rises by 400, to 3,400. The screen bank regulators have long applied flags a deal when the HHI ends above 1,800 and rises by more than 200, and the 2023 federal merger guidelines use a rise of more than 100. Counties stand in for markets in a quick screen. The regulators run theirs on defined banking markets, and they can count thrifts and credit unions at different weights.
How to use it at a bank
- Your own share, county by county, over several surveys. A level tells you where you stand. The direction tells you whether the branch strategy is working.
- Organic growth separate from acquired growth, for your bank and for each competitor. The competitor to worry about is the one growing at offices it already had.
- Office openings and closings in your counties. A closing is the cheapest deposit opportunity a market offers, and the survey shows each one a year later at the latest.
- Each of your offices against the other offices in its county. Deposits per office is a blunt measure, but an office far below the county's typical office needs an explanation.
- The counties next to yours. Size, concentration and how many institutions are already there, before anyone commissions a study.
- The merger screen. Which banks share the most markets with yours, and what combining would do to the HHI in each one.
Frequently asked questions
What is the FDIC Summary of Deposits?
It is the FDIC's annual survey of deposits at every branch office of every FDIC-insured institution, taken as of June 30 and published in the early fall. The 2026 survey covers $19.05 trillion at 75,859 offices of 4,249 institutions. It is the standard public source for deposit market share.
How is deposit market share calculated?
Divide a bank's deposits in an area by the total deposits at all FDIC-insured offices in that area. A bank with $300 million in a county where all offices together hold $2 billion has a 15% share. The county is the usual unit, though regulators analyze competition in banking markets that the Federal Reserve Banks define, which often cross county lines.
Why does a small county show hundreds of billions in deposits?
Because the survey assigns deposits to the office that books them, not to where customers live. Large banks book internet, card, trust and brokered deposits at a single address. In the 2026 survey Minnehaha County, South Dakota shows $479 billion in deposits, and one office holds 96% of it.
Are credit unions included in deposit market share?
Not in the Summary of Deposits, which covers FDIC-insured institutions only. Credit unions report to NCUA and give one deposit total for the whole institution, not a figure for each branch, so adding them to a county takes an estimate.
When is the Summary of Deposits released?
The survey is taken as of June 30 each year, and the FDIC publishes the results in the early fall of the same year, usually in September.
What HHI is considered highly concentrated?
A market with an HHI above 1,800 is treated as highly concentrated. The screen bank regulators have long applied to mergers flags a deal that leaves the HHI above 1,800 and raises it by more than 200 points, and the 2023 federal merger guidelines use a rise of more than 100.
Where these numbers come from
Every figure on this page comes from the FDIC Summary of Deposits as of June 30, 2026, and from the surveys for 2020 through 2025, each built by the same code. No office is left out, and counties where one booking office dominates are labeled, not removed. In BankingLENS, Deposit Share shows a bank's deposits and share by county back to 2020, competitors' organic and acquired growth, office openings and closings, a merger screen and the counties next door. You can see a real bank ranked against its FFIEC peer group on the sample scorecard, or open your own bank in the dashboard. Plans that cover your state or every bank start at $29 a month (pricing).