Old Second Bancorp OSBC Institutional Ownership

Updated Oct 11, 2026

Old Second Bancorp Inc (NASDAQ:OSBC) had 183 institutional holders reporting a position on Form 13F for the quarter ended June 30, 2026.

• Their combined stake equaled 75.65% of outstanding shares in Q2 2026, up from 72.03% in Q1 2026.
• Total shares held in Old Second Bancorp rose 2.61% from Q1 2026, while the number of holders rose 1.10% from Q2 2025.
• Of the 183 holders, 97 added to their positions, 46 reduced their stakes and 40 left their positions unchanged in Q2 2026.
• Altogether, institutional holders owned 38.77Mn OSBC shares at the end of Q2 2026, up 987.79K from the prior quarter and up 6.51Mn from a year earlier.
• BlackRock, Inc. held the largest position in OSBC at 4.3Mn shares as of June 30, 2026, or 8.39% of shares outstanding.
• The largest position increases in OSBC for Q2 2026 were by Citadel Advisors LLC (+243.96K shares), State Street Corp (+239.9K shares), Mariner, LLC (+207.24K shares), American Century Companies Inc (+192.88K shares) and BlackRock, Inc. (+172.44K shares).
• The biggest cuts to OSBC positions during Q2 2026 came from Wellington Management Group LLP (-313.44K shares), Northern Trust Corp (-208.93K shares), JPMorgan Chase & Co (-145.35K shares), UBS Group AG (-112.05K shares) and SEI Investments Co (-85.42K shares).
• Per Business Quant data, the 10 largest holders of Old Second Bancorp at the end of Q2 2026 were BlackRock, Inc. (4.3Mn shares), Dimensional Fund Advisors LP (2.5Mn shares), Vanguard Capital Management LLC (2.18Mn shares), State Street Corp (1.84Mn shares), Davis Asset Management, L.P. (1.8Mn shares), American Century Companies Inc (1.78Mn shares), Goldman Sachs Group Inc (1.62Mn shares), FJ Capital Management LLC (1.46Mn shares), Boston Partners (1.42Mn shares) and Geode Capital Management, LLC (1.35Mn shares).