Lists · Deposits by county
Jefferson County, WI Bank Deposit Market Share
Ixonia Bank holds the largest share of deposits in Jefferson County, WI, 22.8%, followed by Bank of Lake Mills (18.4%) and Premierbank (14.8%). 11 institutions hold $2.34B at 23 offices as of June 30, 2026.
| # | Institution | Deposits | Market share | Share change from 2025 |
|---|---|---|---|---|
| 1 | Ixonia Bank | $533.9M | 22.78% | — |
| 2 | Bank of Lake Mills | $432.3M | 18.45% | — |
| 3 | Premierbank | $347.4M | 14.82% | — |
| 4 | Bank CMG | $345.4M | 14.74% | — |
| 5 | Associated Bank, N.A. | $183.2M | 7.82% | — |
| 6 | BMO Bank N.A. | $129.6M | 5.53% | — |
| 7 | Badger Bank | $113.3M | 4.83% | — |
| 8 | Farmers & Merchants State Bank | $105.7M | 4.51% | — |
| 9 | Bank First, N.A. | $60.9M | 2.60% | — |
| 10 | Johnson Bank | $54.2M | 2.31% | — |
| 11 | First Citizens State Bank | $37.6M | 1.60% | — |
About this list
Deposits are those held at each institution's offices in Jefferson County as of June 30, 2026, from the FDIC Summary of Deposits, whatever state the institution is headquartered in. Market share is the institution's deposits divided by all deposits in the market. Shares are by bank charter, not rolled up to the holding company, and cover FDIC-insured institutions only, so credit unions are not included. Each office is placed in its county and metro area by the FDIC branch directory; the few offices the directory does not list are left out of the market and of every share.
The change from 2025 is not shown for this market: some offices that closed during the year cannot be placed in a single county or metro area, and they hold enough deposits to move the comparison. The 2026 shares are complete.
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