As of November 6, 2026, Old Second Bancorp Inc is a publicly traded company (Nasdaq: OSBC); its largest reported holder is Dimensional, with 5.1% on Schedule 13G of October 8, 2026, then Vanguard (5.03%). The largest insider holding is James Eccher, the chairman and chief executive, with 343,384 shares (0.69% of shares outstanding), per Form 4 of October 1, 2026 (Schedule 13G, October 8, 2026).
Is this your company?
About to sign with, pay or invest in Old Second Bancorp Inc? See the free Snapshot first.
Free to see. No signup.
Is Old Second Bancorp Inc a real, registered company?
- Old Second Bancorp Inc files with the SEC under CIK 357173 (its SEC filings).
- Its shares are listed under the ticker OSBC on Nasdaq (SEC company record).
- Incorporated in Delaware; business address in Aurora, Illinois, as its SEC filings state.
- Court and bankruptcy records: see Before you sign or pay below.
Before you sign or pay
- Court and bankruptcy: No federal court case or bankruptcy filing found under Old Second Bancorp Inc in our court records and SEC 8-K records (as of 2026-11-06).
- Leadership changes: the latest reported is Gary Collins (Form 8-K filed 2026-10-19). Check you are dealing with the people now in charge.
- Ownership: 5%+ holders are reported on Schedule 13D or 13G; the latest names Vanguard (filed 2026-10-30).
Who are Old Second Bancorp Inc's owners and officers?
Old Second Bancorp Inc: incorporated in Delaware; business address in Aurora, Illinois; industry State Commercial Banks (Schedule 13G, 2026-10-30).
| Report | Holder | Share |
|---|---|---|
| Schedule 13G, 2026-10-30 | Vanguard Capital Management | 5.03% |
| Schedule 13G, 2026-10-08 | Dimensional Fund Advisors LP | 5.1% |
| Schedule 13G/A, 2026-03-27 | The Vanguard Group | 0% |
Questions about who owns Old Second Bancorp Inc
Who owns Old Second Bancorp Inc?
On this page, 2 holders' latest ownership filings report 5% or more of Old Second Bancorp Inc: Dimensional Fund Advisors LP (5.1%, Schedule 13G, filed 2026-10-08) and Vanguard Capital Management (5.03%, Schedule 13G, filed 2026-10-30).
Who are the largest shareholders of Old Second Bancorp Inc?
By the share each holder's latest filing reports, the largest holders of Old Second Bancorp Inc on this page are Dimensional Fund Advisors LP (5.1%) and Vanguard Capital Management (5.03%).
When did Dimensional Fund Advisors LP buy into Old Second Bancorp Inc?
The filings give report dates, not purchase dates. The earliest filing from Dimensional Fund Advisors LP on this page is the Schedule 13G, filed 2026-10-08, reporting 5.1%.
Is this an audit or a full list?
Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 3 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.
Want the whole picture on Old Second Bancorp Inc?
Example from a real report (our sample on Target): “The Q2 2026 earnings report, published August 19, 2026, showed adjusted EPS of $2.46 against an expected $2.33” Source: CNBC
A Full Report on Old Second Bancorp Inc: verified, sourced, every claim cited, ready in a few minutes. See pricing.
What the Full Report on Old Second Bancorp Inc covers
The Short Answer
Which Company This Is
What They Do, And How The Money Works
Who Runs It, And How To Reach Them
The Money: Funding, Valuation, Runway
Who Pays Them, And Who They Are Up Against
Warning Bells
Sources
12 cited sources found
Plus the sections for what you are deciding, which you pick after ordering.
A real finished report, first screen. Opens in a new tab.
| Filed | Person | Role | Change | Effective |
|---|---|---|---|---|
| Form 8-K, 2026-10-19 | Gary Collins | departed | 2026-10-31 | |
| Form 8-K, 2026-10-19 | Gary Collins | Director | departed | |
| Form 8-K, 2026-07-08 | John Williams | Director | departed | 2026-07-07 |
| Form 8-K, 2026-06-09 | Dennis Klaeser | Director | departed |
Which insiders own Old Second Bancorp Inc shares?
Directors, officers and holders of 10% or more report their shares on Forms 3, 4 and 5. Each line is the latest such report, largest holding first.
- , the chairman and chief executive: 343,384 shares (0.69% of shares outstanding), 303,399 held directly and 39,985 indirectly (Form 4, 2026-10-01).
- , the president and powersports lending: 250,589 shares (0.51% of shares outstanding) (Form 4, 2026-09-03).
- , a director: 187,461 shares (0.38% of shares outstanding) (Form 4/A, 2026-10-20).
- , a director: 181,013 shares (0.37% of shares outstanding), 36,121 held directly and 144,892 indirectly (Form 4, 2026-01-16).
- , a director: 175,331 shares (0.35% of shares outstanding) (Form 4/A, 2026-10-20).
Shares outstanding: 49,440,752 as of 2026-11-03, from the company's latest SEC cover page.
How much has Old Second Bancorp Inc raised?
No fundraising or offering filing from Old Second Bancorp Inc is on file with us.
Keep reading
More on Old Second Bancorp Inc and the records around it.
Old Second Bancorp Inc elsewhere on the record
- Leadership changes Jul 2026
Companies that share a holder
- Dimensional Fund Advisors LP also filed stake reports on 366 other companies: Acadia Healthcare Co Inc (Oct 2026), ADT Inc (Oct 2026), AGCO Corp (Oct 2026)
- Vanguard Capital Management also filed stake reports on 1495 other companies: A10 Networks Inc (Oct 2026), Altisource Portfolio Solutions SA (Oct 2026), Alto Neuroscience Inc (Oct 2026)
- The Vanguard Group also filed stake reports on 2384 other companies: BellRing Brands, Inc. (Sep 2026), CAL-MAINE FOODS INC (Sep 2026), FTAI Aviation Ltd. (Sep 2026)
Related pages
Filings, cases and notices link to their records. A not-found line names the records searched; it is not proof of absence.
Not for employment, credit, insurance or tenancy decisions.
Cite this page
https://mentionfox.com/who-owns/old-second-bancorp