Bank of Sun Prairie
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Data as of · sourced from FFIEC call reports. How we update
Bank of Sun Prairie is an FDIC-insured commercial bank headquartered in Sun Prairie, WI, established in 1903 (FDIC certificate 13565), and it is supervised by the FDIC. At Q2 2026 it reported total assets of $841.2M, up 16.4% from Q2 2025, the 36th largest of 153 banks headquartered in Wisconsin. Its CET1 capital ratio was 13.27% at Q2 2026, comfortably above the 7% level required once the capital conservation buffer is included.
- Charter
- Commercial bank
- Regulator
- FDIC
- Deposit insurance
- FDIC
- FDIC certificate
- 13565
- Headquarters
- Sun Prairie, WI
- Established
- 1903
- Total assets, Q2 2026
- $841.2M
- Assets vs Q2 2025
- +16.4%
- CET1 ratio, Q2 2026
- 13.27%
- Domestic offices
- 8 FDIC institution directory, current count
- Routing number
- 075903446
- Latest call report
- Q2 2026, FFIEC 051 · Bank of Sun Prairie call report
- Holding company
- BOSP BANCSHARES, INC.
- Asset rank in state
- 36th of 153 in Wisconsin
Bank of Sun Prairie leans heavily on commercial real estate. Its balance sheet stood at $841 million at June 30, 2026, up 16.4% from a year earlier; it is based in Sun Prairie, Wisconsin. It holds commercial real estate loans worth 3.4 times its capital, about triple the median of 1.2 times for the 2,660 banks with $100 million to $1 billion in assets. It also grew deposits 17.4% over the year, 4.3 times the median of 4.0% for banks its size.
Earnings jumped: net income for the quarter was $1.9 million, 130% above the same quarter a year earlier. Over the same year, loans shrank 1.2% and deposits grew 17.4%. Funding is the softer spot: it pays an average of 2.45% on its deposits and borrowings, higher than about three-quarters of banks its size (median 1.80%).
As of June 30, 2026, Bank of Sun Prairie reported a CET1 capital ratio of 13.27%, a return on assets of 0.90%, a nonperforming-loan ratio of 0.07% and a Texas ratio of 0.48%. The figures come from its call report filed with the FFIEC.
Of the 153 banks headquartered in Wisconsin, Bank of Sun Prairie is the 36th largest by total assets at Q2 2026. From Q1 2026 to Q2 2026, its total assets rose 17.4% to $841.2M, loans rose 1.9% and deposits rose 22.5%. Its loan book on June 30, 2026 was led by non-owner-occupied commercial real estate loans, at 26.1% of total loans, followed by multifamily loans at 22.7%. Its 8 offices in the FDIC Summary of Deposits are in 6 cities in WI; its Sun Prairie 3 offices book 78% of its branch deposits. Judged on its Q2 2026 call report, Bank of Sun Prairie meets every capital ratio test for well capitalized.
Headquarters Profile
- Address
- 228 E Main St, Sun Prairie, WI 53590
- County
- Dane
- Metro Area
- Madison, WI
- Charter
- Commercial bank, state charter, Fed non-member, FDIC-supervised
- Primary Regulator
- FDIC
- FDIC Region
- Chicago (Region 9)
- Federal Reserve member
- No
- Federal Reserve district
- District 7, Chicago
- Fiduciary (trust) powers
- Full trust powers granted
- Call Report form
- FFIEC 051
- Established
- August 8, 1903
- Domestic offices
- 8 FDIC institution directory, current count
- Employees (FTE)
- 113
- Domestic deposits
- $719.5M
- Allowance for credit losses
- $7.7M
- Net charge-offs (YTD)
- -$2K
- Average total assets
- $842.8M
- Average total loans
- $599.7M
- Average interest-bearing deposits
- $596.0M
- Tax status
- C corporation
- Ownership
- Stock
- Community bank
- Yes
- FDIC-insured since
- January 6, 1934
- FDIC Cert
- 13565
- Fed RSSD
- 124344
- SEC CIK
- 1423057 → filed by BOSP BANCSHARES, INC.
- Parent Holding Company
- BOSP BANCSHARES, INC. (RSSD 3808113)
Profitability
Q2 annualizedCapital & Liquidity
Balance Sheet
Income Statement
Operating & Funding
Ratios tagged annualized use the Q2 income alone. The UBPR and FDIC annualize the year to date instead. FDIC BankFind divides by the average of quarter-end total assets, the UBPR by RC-K average assets. The YTD margin is the UBPR's tax-equivalent figure over its own average earning assets; FDIC BankFind's margin is not tax-equivalent. How we compute these figures
Quarterly trends
From Q3 2023 to Q2 2026, Bank of Sun Prairie's total assets ranged from $716.6M (Q1 2026) to $841.2M (Q2 2026), and it earned a profit in all 12 quarters. The line under each chart compares Q2 2026 with Q2 2025. How these charts are built
$841.2M total assets against $722.5M; $756.8M total liabilities against $651.8M.
$594.0M net loans and leases against $601.6M; $719.5M total deposits against $613.0M.
$165.0M securities against $71.7M; $42.5M cash and balances due against $19.2M.
$11.5M total interest income against $8.7M; $4.5M total interest expense against $4.5M.
$7.0M net interest income against $4.2M.
$1.1M total noninterest income against $719K; $6.3M total noninterest expense against $4.0M.
-$267K provision for credit losses against -$20K.
$1.9M net income against $821K.
0.90% return on assets against 0.44%; 3.51% net interest margin against 2.40%.
13.27% CET1 capital ratio against 12.49%; 9.99% tier 1 leverage ratio against 10.35%.
Inside the full Bank of Sun Prairie terminal
21 quarters of trends · 8 tabs · peer percentiles · watchlist alerts
Unlock this bank, freeWatch flags
Automated conditions triggered on this bank's latest filing. Advisory only; see the source metric pages for full context. Each flag is tagged Regulatory when it cites an official supervisory threshold, or BRR analysis when it's our own band, informed by our data and models.
Commercial real estate loans exceed 300% of total capital, the threshold at which the 2006 interagency guidance flags a bank for heightened supervisory scrutiny. CRE concentration has been the central stress vector for regional banks since 2023. 2006 Interagency CRE Concentration Guidance (SR 07-1).
Bank of Sun Prairie rankings
Its closest position to the top of a national ranking is 1,194 of 4,196, for total assets; its furthest is 2,982 of 3,606, for efficiency ratio.
Banks merged into Bank of Sun Prairie
- Banner Banks, effective May 4, 2026
Quarterly trend: last 8 quarters
From Q3 2024 to Q2 2026, its return on assets ran from 0.19% (Q3 2024) to 0.90% (Q2 2026) and its net interest margin ran from 2.00% (Q4 2024) to 3.51% (Q2 2026).
| Quarter | CET1 | ROA | NPL | Texas | NIM |
|---|---|---|---|---|---|
| Q2 2026 | 13.27% | 0.90% | 0.07% | 0.48% | 3.51% |
| Q1 2026 | 11.64% | 0.41% | 0.05% | 0.39% | 2.55% |
| Q4 2025 | 11.75% | 0.62% | 0.05% | 0.39% | 2.66% |
| Q3 2025 | 12.49% | 0.59% | 0.00% | 0.03% | 2.61% |
| Q2 2025 | 12.49% | 0.44% | 0.00% | 0.04% | 2.40% |
| Q1 2025 | 12.44% | 0.27% | 0.05% | 0.36% | 2.14% |
| Q4 2024 | 12.15% | 0.36% | 0.00% | 0.00% | 2.00% |
| Q3 2024 | 11.30% | 0.19% | 0.00% | 0.00% | 2.04% |
Swipe the table sideways to see every column.
Branch Network
View all 8 branches → Branch count from the FDIC Summary of Deposits, June 30, 2026. The domestic office count above is the FDIC's current figure, so the two can differ.
| Branch | Location | ZIP | Deposits |
|---|---|---|---|
| Bank of Sun Prairie (main office) | Sun Prairie , WI | 53590 | $423.3M |
| Grand Avenue Office Branch | Sun Prairie , WI | 53590 | $135.9M |
| Hatley Branch | Hatley , WI | 54440 | $51.6M |
| Cottage Grove Branch | Cottage Grove , WI | 53527 | $47.0M |
| Antigo Branch | Antigo , WI | 54409 | $28.5M |
| Wittenberg Branch | Wittenberg , WI | 54499 | $16.8M |
| Banner Banks Branch | Birnamwood , WI | 54414 | $16.3M |
| Sun Prairie West High School Branch | Sun Prairie , WI | 53590 | $49K |
Events & Regulatory History
Mergers, charter changes, enforcement actions, FDIC assistance, and (if applicable) failure events recorded against this institution. Click a year to see what else was happening across US banking that year.
| Date | Category | Event | Source |
|---|---|---|---|
| May 4, 2026 | Structure Change | Acquired Banner Banks Charter Discontinued (Merger or Purchase & Assumption) for the acquired bank | FFIEC NIC |
| May 3, 2026 | Merger | Participated in Absorption/Consolidation/Merger | FDIC |
Sourced from the bank event history (FDIC, Federal Reserve NIC, OCC, and OTS). Showing the most recent 2 events.
Regulatory record
Facts as filed or published, not a rating.
- Deposit market share
- 0.3% of deposits in WI, rank 43 of 185 institutions
- Period: June 30, 2026. Source: FDIC Summary of Deposits.
- Mortgage lending (HMDA)
- 221 applications, 153 loans originated, $50.3M originated, across 1 states
- Period: Calendar year 2025. Source: FFIEC HMDA loan application register.
- SBA 7(a) lending
- 1 loans, $300K approved, $300K average. 0.00% of that year's loans have since been charged off
- Period: Federal fiscal year 2025 (October to September). Source: SBA 7(a) and 504 loan data (FOIA).
- Not on file
- Enforcement actions, Consumer complaints, CFPB enforcement, CRA examination rating. No record from these sources, which is not the same as a clean record. Sources
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Frequently asked about Bank of Sun Prairie
What are Bank of Sun Prairie's total assets?
As of the Q2 2026 filing, Bank of Sun Prairie reported total assets of $841.2 million in its FFIEC call report.
Where is Bank of Sun Prairie headquartered?
It is headquartered in Sun Prairie, WI, United States.
When was Bank of Sun Prairie founded?
It was established in 1903, per the FDIC institution directory.
Is Bank of Sun Prairie FDIC-insured?
Yes. It is an FDIC-insured commercial bank (FDIC Certificate #13565). Deposits are insured up to $250,000 per depositor, per insured bank, for each account ownership category, per FDIC rules.
Who regulates Bank of Sun Prairie?
Bank of Sun Prairie's primary federal regulator is the FDIC.
What is Bank of Sun Prairie's CET1 capital ratio?
It reported a Common Equity Tier 1 (CET1) capital ratio of 13.27% in its Q2 2026 call report, comfortably above the 7% level required once the capital conservation buffer is included.
How many branches does Bank of Sun Prairie operate?
It operates 8 domestic offices, per the FDIC institution directory. That count includes administrative and limited-service offices as well as full-service branches.
What is Bank of Sun Prairie's Texas Ratio?
Its Texas Ratio is 0.48% in its Q2 2026 call report, within the healthy range (at or below 50%, the level at which problem assets reach half of the capital cushion). The Texas Ratio measures non-performing assets against the bank's capital and reserves.
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