SCHEDULE: Dimensional Fund Advisors Reports 5.1% Stake in Old Second Bancorp

Dimensional Fund Advisors LP has filed a Schedule 13G, disclosing beneficial ownership of 5.1% of Old Second Bancorp Inc.'s common stock as of September 30, 2026.

Summary

• Dimensional Fund Advisors LP (DFA) has filed a Schedule 13G, indicating it beneficially owns 2,575,752 shares of Old Second Bancorp Inc. common stock.
• This ownership stake represents 5.1% of the class of securities.
• The filing is made under Rule 13d-1(b), classifying DFA as an investment adviser.
• DFA states that the securities are held in the ordinary course of business and not for the purpose of influencing control of the issuer.
• The reporting date for the event requiring this filing is September 30, 2026.

Sentiment

Score: 3

Explanation: StockSavvy.ai views this filing as neutral to slightly negative, as it primarily reports a passive ownership stake without new strategic information or significant changes in holdings.

Positives

• Dimensional Fund Advisors LP, a significant investment manager, holds a substantial stake, which can sometimes be interpreted as a vote of confidence in the company's long-term prospects.
• The filing confirms DFA's role as a passive investor, not seeking to influence control, which suggests stability from this particular shareholder.

Negatives

• The filing does not provide any new strategic insights or operational updates from Old Second Bancorp itself, as it is a disclosure by a third-party investor.
• The passive nature of the investment means there's no immediate indication of active support or strategic involvement from DFA to drive company growth.

Risks

• While DFA disclaims beneficial ownership for purposes other than Section 13(d), any significant shift in their holdings could impact the stock price.
• The filing does not detail specific risks related to Old Second Bancorp's operations, but rather focuses on DFA's investment position.

Future Outlook

This filing does not contain forward-looking statements or guidance from Old Second Bancorp. It is a disclosure of ownership by Dimensional Fund Advisors LP.

Management Comments

• "In its role as investment advisor, sub-adviser and/or manager, Dimensional Fund Advisors LP or its subsidiaries (collectively, 'Dimensional') may possess voting and/or investment power over the securities of the Issuer that are owned by the Funds, and may be deemed to be the beneficial owner of the shares of the Issuer held by the Funds."
• "However, all securities reported in this schedule are owned by the Funds. Dimensional disclaims beneficial ownership of such securities."
• "The filing of this Schedule 13G shall not be construed as an admission that the reporting person or any of its affiliates is the beneficial owner of any securities covered by this Schedule 13G for any other purposes than Section 13(d) of the Securities Exchange Act of 1934."
• "By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under 240.14a-11."

Industry Context

StockSavvy.ai notes that this filing is a routine Schedule 13G, indicating a significant institutional investor's passive stake. Such filings are common for large asset managers like Dimensional Fund Advisors when their holdings in a public company cross a reporting threshold. It does not reflect new strategic initiatives by Old Second Bancorp but rather the investment decisions of DFA.

Stakeholder Impact

• Shareholders: The passive stake by a large asset manager like DFA can provide a degree of stability to the stock. However, any future changes in DFA's holdings could impact share price.
• Management of Old Second Bancorp: The filing indicates a significant institutional investor, which may influence future investor relations efforts.
• Creditors: No direct impact is indicated by this filing.

Next Steps

• Dimensional Fund Advisors LP will continue to hold its shares in Old Second Bancorp Inc. as part of its investment management activities.
• Future filings will be made if DFA's beneficial ownership changes significantly.

Key Dates

Keywords

Old Second Bancorp, Dimensional Fund Advisors, Schedule 13G, Beneficial Ownership, Investment Adviser, Common Stock, Shareholder