10 FDIC-insured banks operate 13 branches in Sac County, Iowa, holding $551.2M in total deposits as of the 2026 FDIC Summary of Deposits. Iowa State Bank leads the market with 34.0% share. Deposit market share is the clearest available measure of competitive position in a local market: it reflects where households and businesses actually keep their money, rather than where institutions advertise or how many branches they operate.
Ranked by deposits held within county borders. A bank's county deposits are the sum across all of its branches in that county, so an institution with several locations appears once. Figures are as of June 30, 2026, the annual reporting date for the FDIC Summary of Deposits.
| Rank | Bank | Deposits | Share | Branches |
|---|---|---|---|---|
| 1 | Iowa State Bank | $187.5M | 34.01% | 3 |
| 2 | United Bank of Iowa | $96.7M | 17.53% | 2 |
| 3 | Bank Midwest | $57.5M | 10.43% | 1 |
| 4 | Iowa Trust & Savings Bank | $46.7M | 8.47% | 1 |
| 5 | State Bank of Schaller | $34.9M | 6.34% | 1 |
| 6 | Westside State Bank | $32.0M | 5.80% | 1 |
| 7 | Farmers State Bank | $31.5M | 5.71% | 1 |
| 8 | The Citizens First National Bank of Storm Lake | $26.6M | 4.83% | 1 |
| 9 | First State Bank | $23.7M | 4.31% | 1 |
| 10 | The Shelby County State Bank | $14.2M | 2.57% | 1 |
The FDIC Summary of Deposits is an annual survey of branch office deposits filed by every FDIC-insured institution as of June 30 each year. It is the authoritative source for local deposit market share and is the dataset regulators use when assessing competitive effects of bank mergers. Because it is annual, it reflects a point in time rather than current balances. Vault republishes it without modification, free to access and free to cite. Available to AI agents at vaultbot.ai/mcp.