Old Second National Bank
Aurora, IL · Owner: Old Second Bancorp, Inc.
$6.9B
total assets, June 30, 2026
$6.9B
total assets, June 30, 2026
Old Second National Bank is a national bank based in Aurora, IL, owned by Old Second Bancorp, Inc. (OSBC). As of June 30, 2026 it held $6.9 billion in assets and $5.5 billion in deposits; assets were up 20.4% from a year before. It has 57 branches.
Updated Oct 11, 2026 · numbers as of June 30, 2026
Total assets
$6.9B
+20.4% in a year · +0.2% in a quarter
Deposits
$5.5B
+12.3% in a year · -2.4% in a quarter
Loans
$5.2B
+31.1% in a year · +1.1% in a quarter
Profit so far
$57.9M
Jan 1 to Jun 30, 2026 · +26.3% in a year
Capital ratio
12.05%
+0.46 pts in a year
Return on assets
1.69%
+0.07 pts in a year
Facts
- Type
- National bank
- Head office
- 37 S River St, Aurora, IL, 60506
- County
- Kane
- Holding company
- Old Second Bancorp, Inc. (OSBC)
- Established
- Nov 21, 1887
- Employees
- 1,052
- Branches
- 57
- Website
- www.oldsecond.com
- Id
- b3603
Quarter by quarter
March 31, 1984 to June 30, 2026
Assets, deposits and loans
Each quarter end, US dollars
Profit by quarter
Net income of each quarter, the last 12
Ratios
Percent. Return on assets and net interest margin are yearly rates.
Branches
57 offices as of June 30, 2026, holding $5.5 billion in deposits
Branch map
Every branch, sized by its deposits
| State | Branches | Deposits | Share |
|---|---|---|---|
| Illinois | 57 | $5.5B | 100.0% |
| Largest branches | Place | Deposits |
|---|---|---|
| Old Second National Bank (main office) | Aurora, IL | $867M |
| Downtown Chicago Branch | Chicago, IL | $440M |
| Westmore Branch | Lombard, IL | $299M |
| Cass Avenue Branch | Darien, IL | $247M |
| Oak Brook Branch | Oak Brook, IL | $241M |
| Evergreen Park Branch | Evergreen Park, IL | $180M |
| Countryside Branch | Yorkville, IL | $168M |
| Oswego Branch | Oswego, IL | $158M |
| Elburn Branch | Elburn, IL | $142M |
| West Galena Branch | Aurora, IL | $123M |
Related pages
Questions and answers
How big is Old Second National Bank?
$6.9 billion in total assets and $5.5 billion in deposits as of June 30, 2026, with assets up 20.4% from a year before. Its loans were $5.2 billion.
How many branches does Old Second National Bank have?
57 branches in Illinois as of June 30, 2026.
Is Old Second National Bank profitable?
Yes: it earned $57.9 million from January 1 to June 30, 2026 (up 26.3% from the same months a year before). Its return on assets was 1.69% a year; about 1% is typical.
Who owns Old Second National Bank?
Old Second National Bank is owned by Old Second Bancorp, Inc., its holding company, which is listed as OSBC.
Official public data from the reports every insured bank files each quarter. Profit so far runs from January 1 to the quarter end. Branch deposits are counted once a year, as of June 30. New quarters appear about two months after the quarter ends.