OLD Second Bancorp Inc (OSBC) Form 4 Filed by Jill E York, Oct 21, 2026

SEC Form 4 · No Market Transaction
Small Acquisition

Non-market transaction reported.

Reporting Owner
Jill E York
Director
TXN 2026-08-10 · FILED 2026-10-21
Equity Position 30.3K sh 30,034 → 30,344
Equity Change +1.0% shares held after vs before
Filing Lag 50 business days late vs 2-day SEC deadline
Form 4 · Statement of Changes in Beneficial Ownership

OLD Second Bancorp Inc

OSBC CIK 0000357173
All OLD Second Bancorp Inc insider activity
Filing Date
2026-10-21
Report Date
2026-10-21
Accession No.
0001244438-26-000006
Accepted At
2026-10-21 21:10 UTC
Reporting Owner
Name Relationship
Jill E York CIK 0001244438
Director
Jill E York at OLD Second Bancorp Inc Full insider history
Bought (12 mo) —
Sold (12 mo) —
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All filings by this insider at OLD Second Bancorp Inc
Non-Derivative Securities Transactions
Title Date Type Shares Price Net Total Post-Txn Ownership
Old Second Bancorp, Inc. Common StockF1F2 2021-05-11 L - Small Acquisition 14.2083 A $14.08 +$200 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2021-08-11 L - Small Acquisition 17.5446 A $11.44 +$201 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2021-11-09 L - Small Acquisition 14.5974 A $13.81 +$202 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2022-02-08 L - Small Acquisition 14.0252 A $14.43 +$202 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2022-05-10 L - Small Acquisition 14.3579 A $14.14 +$203 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2022-08-09 L - Small Acquisition 14.5777 A $13.98 +$204 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2022-11-08 L - Small Acquisition 12.0515 A $16.97 +$205 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2023-02-07 L - Small Acquisition 11.9166 A $17.21 +$205 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2023-05-09 L - Small Acquisition 18.4285 A $11.16 +$206 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2023-08-08 L - Small Acquisition 12.9172 A $15.99 +$207 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2023-11-07 L - Small Acquisition 14.5225 A $14.27 +$207 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2024-02-06 L - Small Acquisition 15.4522 A $13.46 +$208 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2024-05-06 L - Small Acquisition 14.46 A $14.43 +$209 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2024-08-05 L - Small Acquisition 14.0955 A $14.86 +$209 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2024-11-04 L - Small Acquisition 15.6156 A $16.15 +$252 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2025-02-10 L - Small Acquisition 13.3087 A $19.02 +$253 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2025-05-05 L - Small Acquisition 15.5779 A $16.30 +$254 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2025-08-04 L - Small Acquisition 15.3405 A $16.61 +$255 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2025-11-10 L - Small Acquisition 16.2619 A $18.35 +$298 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2026-02-09 L - Small Acquisition 14.1217 A $21.21 +$300 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2026-05-11 L - Small Acquisition 14.3767 A $20.90 +$300 4,319.6382 Direct
Old Second Bancorp, Inc. Common StockF1F2 2026-08-10 L - Small Acquisition 11.8801 A $25.38 +$302 4,319.6382 Direct
Non-Derivative Holdings
Title Shares Held Ownership
Old Second Bancorp, Inc. Common StockF3 15,430 Indirect Living Trust
Restricted Stock Units 10,595 Direct
Footnotes (3)
F1
Represents shares acquired through the automatic reinvestment of cash dividends paid on shares of the Issuer's common stock held in the Reporting Person's individual retirement account, under a dividend reinvestment feature offered by the account custodian. The custodian's reinvestment feature is not a plan sponsored by the Issuer. These acquisitions were not previously reported because of an administrative oversight, and are reported herein to correct the omission. Show more
F2
The amount of securities beneficially owned represents the Reporting Person's holdings in her individual retirement account as of the date hereof, after giving effect to all dividend reinvestment transactions reported herein. The transactions reported herein were not previously reported. Show more
F3
The Reporting Person additionally beneficially owns 15,430 shares through her living trust as of October 15, 2026. This amount reflects her current trust holdings and supersedes the trust balance previously reported. Show more

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Institutional Holders
13F holders · Jun 30, 2026 184 institutional managers reporting a position
Largest by reported value
  1. Black Rock, Inc. $100M
  2. Dimensional Fund Advisors Lp $58.3M
  3. Vanguard Capital Management Llc $50.8M
5%+ Holders · 13D/G 1 filer

Latest Schedule 13D/G per filer; stakes the filer reported closed are left out.

Other insiders at OLD Second Bancorp Inc
All OLD Second Bancorp Inc insider activity
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