Who owns Old Second Bancorp, Inc.?
Institutional ownership of OSBC from SEC Form 13F filings across 131 reporting managers. All positions are from one synchronized reporting period — 2026-06-30 books, filed up to 45 days after quarter end — so every row is comparable.
131
13F holders
$521.6M
value, 2026 filers
44.3%
of shares outstanding (22.8M sh)
15
new positions (2026 filers)
Top institutional holders
ordered by shares owned · positions as of 2026-06-30· % of fund = share of the manager's own book · % of co. = share of OSBC's shares outstanding
| # | Manager | Shares | Value | % of fund | % of co. | Δ shares QoQ |
|---|---|---|---|---|---|---|
| 1 | BlackRock, Inc. | 4.3M | $100.2M | 0.0% | 8.4% | +4.2% |
| 2 | VANGUARD CAPITAL MANAGEMENT LLC | 2.2M | $50.8M | 0.0% | 4.2% | -51.6% |
| 3 | AMERICAN CENTURY COMPANIES INC | 1.8M | $41.6M | 0.0% | 3.5% | +12.1% |
| 4 | GOLDMAN SACHS GROUP INC | 1.6M | $37.9M | 0.0% | 3.2% | -3.9% |
| 5 | GEODE CAPITAL MANAGEMENT, LLC | 1.3M | $31.5M | 0.0% | 2.6% | +5.3% |
| 6 | MANUFACTURERS LIFE INSURANCE COMPANY, THE | 872,651 | $20.4M | 0.0% | 1.7% | -0.7% |
| 7 | VANGUARD PORTFOLIO MANAGEMENT LLC | 819,368 | $19.1M | 0.0% | 1.6% | +15.0% |
| 8 | ALLIANCEBERNSTEIN L.P. | 641,845 | $12.9M | 0.0% | 1.2% | -7.1% |
| 9 | JPMORGAN CHASE & CO | 555,602 | $12.9M | 0.0% | 1.1% | -20.7% |
| 10 | NORTHERN TRUST CORP | 555,408 | $13.0M | 0.0% | 1.1% | -27.3% |
| 11 | WELLINGTON MANAGEMENT GROUP LLP | 544,345 | $12.7M | 0.0% | 1.1% | -36.5% |
| 12 | Nuveen, LLC | 492,162 | $11.5M | 0.0% | 1% | +17.3% |
| 13 | Sixth Street Partners Management Company, L.P.NEW | 431,304 | $10.1M | 1.7% | 0.8% | new |
| 14 | CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 431,304 | $10.1M | 0.0% | 0.8% | +0.1% |
| 15 | BANK OF AMERICA CORP /DE/ | 372,648 | $8.7M | 0.0% | 0.7% | +12.5% |
| 16 | Bank of New York Mellon Corp | 342,013 | $8.0M | 0.0% | 0.7% | +1.4% |
| 17 | VANGUARD FIDUCIARY TRUST CO | 341,200 | $8.0M | 0.0% | 0.7% | +1.7% |
| 18 | MORGAN STANLEY | 318,318 | $7.4M | 0.0% | 0.6% | +14.3% |
| 19 | CITADEL ADVISORS LLC | 304,021 | $7.1M | 0.0% | 0.6% | +406.2% |
| 20 | FRANKLIN RESOURCES INC | 259,324 | $6.0M | 0.0% | 0.5% | +194.1% |
| 21 | Thrivent Financial for Lutherans | 242,278 | $5,650 | 0.0% | 0.5% | +69.3% |
| 22 | Mariner, LLC | 225,303 | $5.3M | 0.0% | 0.4% | +1147.0% |
| 23 | ARROWSTREET CAPITAL, LIMITED PARTNERSHIP | 210,745 | $4.9M | 0.0% | 0.4% | +49.4% |
| 24 | TWO SIGMA INVESTMENTS, LP | 200,819 | $4.7M | 0.0% | 0.4% | +198.1% |
| 25 | Squarepoint Ops LLC | 167,884 | $3.9M | 0.0% | 0.3% | -1.6% |
Source: SEC Form 13F-HR filings (institutional managers over $100M in US-listed positions). 13Fs disclose long positions only, up to 45 days after quarter end; each manager's latest filed quarter is shown per row and dollar values are the manager's filed marks. Aggregates labeled "2026 filers" count only managers whose latest book is a 2026 quarter. Related: valuation · options positioning · supply chain. Research, not investment advice.