Old Second National Bank
Old Second National Bank is a national bank based in Aurora, Illinois, with $6.9 billion in assets and $5.5 billion in deposits as of 30 June 2026. The FDIC’s 2026 branch survey counts 57 branches in 7 counties.
| FDIC certificate | 3603 |
|---|---|
| Charter class | National bank |
| Established | Not published |
| Assets | $6.9 billion |
| Deposits | $5.5 billion |
| Offices | 57 |
| Net income, year to date | $57.9 million |
| Return on assets | 1.69% |
| Website | www.oldsecond.com |
| Mortgage lending | Old Second National Bank reported 1,172 mortgages made in 2025. |
Branches by county, 2026
| County | Branches | Deposits |
|---|---|---|
| DuPage County, IL | 22 | $1.8 billion |
| Kane County, IL | 14 | $1.9 billion |
| Cook County, IL | 10 | $1.0 billion |
| Will County, IL | 5 | $250.5 million |
| Kendall County, IL | 4 | $400.8 million |
| LaSalle County, IL | 1 | $51.5 million |
| DeKalb County, IL | 1 | $40.2 million |
Closed since the 2025 survey
1 branch in the 2025 survey has no 2026 row: closed, sold, or moved.
- 8301 Cass Ave, Darien, IL (DuPage)
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Counts, medians and denial shares are computed from the Home Mortgage Disclosure Act loan-level file for 2025, published by the Consumer Financial Protection Bureau through the FFIEC: every application a covered lender received, as the lender reported it. Branches and deposits come from the FDIC Summary of Deposits as of 30 June 2026, and bank balance sheets from the FDIC institutions directory. A median rate is what borrowers got, not what you will be offered — it depends on the loan, the property, your credit and the market on the day, and no figure here is a quote. A median over fewer than 10 loans is not shown: it is a number with no meaning and a real person's rate half-exposed. Those cells say "under 10 loans" and the count is still published. This is information, not advice, and no lender pays to appear.