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Rock County, WI Bank Deposit Market Share

BMO Bank N.A. holds the largest share of deposits in Rock County, WI, 15.1%, followed by Johnson Bank (14.3%) and Bank First, N.A. (13.9%). 18 institutions hold $3.45B at 34 offices as of June 30, 2026, down 1.3% from 2025.

Institutions: 18 Offices: 34 Deposits: $3.45B Survey: FDIC Summary of Deposits, June 30, 2026

Largest share changes since 2025

Gained: Bank First, N.A. (13.92 points, new to this market); Johnson Bank (1.69 points); The Bank of Brodhead (0.53 points).

Lost: First Mid Bank & Trust, N.A. (-1.74 points); Bank CMG (-0.09 points); BMO Bank N.A. (-0.09 points).

# Institution Offices Deposits Market share Share change from 2025 Deposit change
1 BMO Bank N.A. 5 $522.2M 15.12% -0.09 pts -1.9%
2 Johnson Bank 2 $495.5M 14.35% +1.69 pts 11.9%
3 Bank First, N.A. 4 $480.7M 13.92% +13.92 pts New
4 Associated Bank, N.A. 2 $375.8M 10.88% +0.01 pts -1.2%
5 First Mid Bank & Trust, N.A. 3 $359.0M 10.40% -1.74 pts -15.5%
6 JPMorgan Chase Bank, N.A. 2 $267.9M 7.76% +0.13 pts 0.4%
7 Bank of Milton 2 $193.7M 5.61% +0.41 pts 6.5%
8 Lake Ridge Bank 2 $149.7M 4.33% +0.35 pts 7.4%
9 First Community Bank 1 $141.8M 4.11% +0.14 pts 2.2%
10 The Bank of Brodhead 2 $99.9M 2.89% +0.53 pts 20.7%
11 Old National Bank 1 $96.4M 2.79% +0.20 pts 6.3%
12 Town Bank, N.A. 2 $76.3M 2.21% +0.37 pts 18.3%
13 U.S. Bank N.A. 1 $59.9M 1.74% +0.34 pts 23.1%
14 Bank CMG 1 $42.1M 1.22% -0.09 pts -7.9%
15 CBI Bank & Trust 1 $38.7M 1.12% +0.16 pts 15.1%
16 Premierbank 1 $28.0M 0.81% +0.14 pts 20.1%
17 Farmers & Merchants Union Bank 1 $19.5M 0.57% -0.06 pts -10.1%
18 Sauk Valley Bank & Trust Company 1 $6.4M 0.18% +0.11 pts 130.0%

About this list

Deposits are those held at each institution's offices in Rock 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.

Share change compares the institution's share in 2025 and 2026 in percentage points. Deposit change compares its deposits here in the two years and includes deposits that moved through mergers and branch sales; "New" means it had no offices here a year earlier. Offices that closed during the year are placed by their ZIP code or city.

Wider markets

Wisconsin deposits by institution Janesville-Beloit, WI metro area Wisconsin bank directory

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