Polk County, IA

Polk County, Iowa, a core county of the Des Moines-West Des Moines-Ames, IA market, holds $29.8B in deposits across 41 insured institutions and 130 branches. Principal Bank is the largest deposit holder at 28.1% share. The top three banks hold 54% of deposits, which places the county in the Moderate band. Deposits have grown 50.2% since 2020 while the branch count fell by 6.5%. It produces $50.5B of output, ranking #91 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: 139 in 2020 to 130 in 2025. Institutions: 36 to 41. Top-three share: 53% to 54%.

Institutions by deposits

The 41 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 Des Moines-West Des Moines-Ames market

Polk County is one of 10 counties that make up the Des Moines-West Des Moines-Ames, IA market, a Combined Statistical Area (ranked #53 of 293 U.S. markets by economic output). It produces 69.4% of the market’s output and holds 73.0% of its deposits.

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