Old Second Bancorp, Inc. (OSBC) is a Delaware-incorporated bank holding company founded in 1981, headquartered in Aurora, Illinois. Its wholly-owned subsidiary, Old Second National Bank, is a nationally chartered commercial bank operating 55 banking centers across Cook, DeKalb, DuPage, Kane, Kendall, LaSalle, and Will counties in Illinois — primarily in the western and southern portions of the Chicago metropolitan area.
Business Overview
Old Second conducts a full-service community banking and trust business. Core offerings include commercial and consumer deposit accounts (checking, savings, money market, time deposits, IRAs), commercial and industrial lending, commercial real estate lending, residential mortgages, construction lending, equipment leasing, home equity lines of credit, wealth management and trust services, and a broad suite of electronic banking and cash management services. As of December 31, 2025, the bank had approximately $2.29 billion in assets under administration and/or management through its wealth management division.
**2025 Acquisition: Bancorp Financial / Evergreen...
AI-generated summary of Item 1 (Business) from the 10-K filed Feb 26, 2026 — View filing on SEC.gov. May contain errors — refer to the filing for authoritative information.
Across SEC filings
Institutional holders · 13F
Q2 2026| Largest holders | Reported value |
|---|---|
| BlackRock Inc | $100.2M |
| DIMENSIONAL FUND ADVISORS LP | $58.3M |
| VANGUARD CAPITAL MANAGEMENT LLC | $50.8M |
| STATE STREET CORPORATION | $42.9M |
| Davis Asset Management L P | $42.0M |
Annual results · 10-K
Fiscal 2025- Net income
- $80.3M
As reported in the fiscal 2025 annual report.
Funds & ETFs · N-PORT
Insider trades · Form 4
Latest filings
- James Eccher 2026-10-01 Gift/Other
- Bradley S. Adams 2026-10-01 Gift/Other
- Richard A Gartelmann Jr 2026-10-01 Gift/Other
- Donald Pilmer 2026-10-01 Gift/Other
- Gary S Collins 2026-10-01 Gift/Other
5%+ holders · 13D/G
1 filer| Filer | % of class | Filed |
|---|---|---|
| DIMENSIONAL FUND ADVISORS LP 13G | 5.1% | 2026-10-08 |
Latest Schedule 13D or 13G from each filer; stakes a filer has reported closed are left out.
Securities
| CUSIP | Security | Type |
|---|---|---|
| 680277100 | OSBC OLD SECOND BANCORP INC I L L | Common stock |