King County, WA

King County, Washington, a core county of the Seattle-Tacoma, WA market, holds $104.2B in deposits across 38 insured institutions and 411 branches. Bank of America is the largest deposit holder at 29.5% share. The top three banks hold 58% of deposits, which places the county in the Moderate band. Deposits have fallen 12.9% since 2021 while the branch count fell by 17.5%. It produced $409.2B of real gross domestic product in 2024, ranking #5 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: 498 in 2021 to 411 in 2026. Institutions: 45 to 38. Top-three share: 57% to 58%.

Institutions by deposits

The 38 insured institutions with a branch presence in this county, per the FDIC Summary of Deposits, June 30, 2026. Five-year change compares the same institution’s county deposits in 2021 and 2026. 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 2021 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 Seattle-Tacoma market

King County is one of 9 counties that make up the Seattle-Tacoma, WA market, a Combined Statistical Area (ranked #9 of 293 U.S. markets by economic output). It produces 73.5% of the market’s output and holds 65.8% of its deposits.

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