Plymouth County, Iowa, a core county of the Sioux City-Le Mars, IA-NE-SD market, holds $1.4B in deposits across 8 insured institutions and 15 branches. American Bank, National Association is the largest deposit holder at 30.9% share. The top three banks hold 73% of deposits, which places the county in the Concentrated band. Deposits have grown 30.0% since 2020. It produces $1.6B of output, ranking #1,029 of the 1,523 ranked counties by economic output.
Ranks show where the county stands among the 1,523 ranked counties (those within a Combined or Metropolitan Statistical Area that have a branch). They describe relative position, not a rating of market quality or suitability.
Deposit trend
Branches: 15 in 2020 to 15 in 2025. Institutions: 9 to 8. Top-three share: 64% to 73%.
Institutions by deposits
| Institution | Deposits | Share | 5‑yr deposits |
|---|---|---|---|
| American Bank | $432M | 30.9% | +48% |
| Primebank | $370M | 26.5% | +33% |
| Iowa State Bank | $212M | 15.2% | +121% |
| Northwest Bank | $91M | 6.5% | +1% |
| Midstates Bank | $88M | 6.3% | -25% |
| Peoples Bank | $79M | 5.7% | +56% |
| United Bank of Iowa | $77M | 5.5% | +98% |
| The Security National Bank of Sioux City, Iowa | $49M | 3.5% | +4% |
The 8 insured institutions with a branch presence in this county, per the FDIC Summary of Deposits, June 30, 2025. Five-year change compares the same institution’s county deposits in 2020 and 2025. Institutions are tracked by FDIC certificate number, and where an institution acquired another bank, the acquired bank’s prior deposits are folded into the baseline so the change reflects the combined, continuing franchise rather than reading as new. “No 2020 presence” means neither the institution nor a bank it later absorbed reported deposits in this county that year. Deposit figures are nominal and are not adjusted for inflation.
Part of the Sioux City-Le Mars market
Plymouth County is one of 4 counties that make up the Sioux City-Le Mars, IA-NE-SD market, a Combined Statistical Area (ranked #187 of 293 U.S. markets by economic output). It produces 14.6% of the market’s output and holds 23.7% of its deposits.
| Measure | Plymouth County | Share of parent market |
|---|---|---|
| 2024 GDP | $1.6B | 14.6% |
| Deposits | $1.4B | 23.7% |
| Population | 25,697 | 15.0% |
View the full Sioux City-Le Mars market profile →
Recruiting in Plymouth County
Deposits are held closely by the largest banks, which often means the bankers worth recruiting are inside a small number of institutions. Who holds the deposits, and how contested the market is, shapes both the runway for growth and the competition you would be recruiting against. We recruit commercial relationship managers, banking teams, and market leaders for banks building in markets like Plymouth County.
See how we help banks recruit commercial banking talent