| # | Institution | Type | Branches | Deposits | Share |
|---|---|---|---|---|---|
| 1 | First Interstate Bank | Bank | 2 | $223.2M | 36.17% |
| 2 | Bank of The Rockies | Bank | 3 | $124.5M | 20.18% |
| 3 | American Bank | Bank | 1 | $116.7M | 18.91% |
| 4 | Opportunity Bank of Montana | Bank | 1 | $63.8M | 10.33% |
| 5 | Wells Fargo Bank, National Association | Bank | 1 | $59.4M | 9.62% |
| 6 | Sky Federal Credit Union | Credit union | 1 | $29.5M* | 4.78% |
* Credit-union deposits are estimated (June total shares spread evenly across branches).
| Year | Deposits | Institutions | Branches | Leader | Top share | HHI |
|---|---|---|---|---|---|---|
| 2026 | $617.1M | 6 | 9 | First Interstate Bank | 36.2% | 2,295 |
| 2025 | $606.1M | 6 | 9 | First Interstate Bank | 36.9% | 2,340 |
| 2024 | $583.2M | 6 | 9 | First Interstate Bank | 39.1% | 2,438 |
| 2023 | $569.5M | 6 | 9 | First Interstate Bank | 38.5% | 2,370 |
| 2022 | $609.5M | 6 | 9 | First Interstate Bank | 39.2% | 2,417 |
Every institution above links to its profile — ratios, peer medians and this quarter’s change signals. Pro adds the full table, share movement and CSV export.