OLD SECOND BANCORP INC (OSBC) Institutional Shareholders
OLD SECOND BANCORP INC (OSBC) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026. The institutional investors covered on this page collectively reported approximately $894.91M in OSBC holdings during the latest filing period.
Blackrock, Inc. is currently the largest disclosed institutional shareholder of OSBC tracked by InsiderSet, reporting ownership valued at approximately $100.25M in its June 30, 2026 SEC Form 13F filing. Based on current market prices and the latest disclosed share count, the position is now estimated to be worth approximately $111.38M, representing an estimated gain of +11.11% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 53% of the total disclosed OSBC value among the investors covered in this analysis. Major shareholders include Blackrock, Inc., Dimensional Fund Advisors Lp, Vanguard Capital Management Llc, and several other long-term asset managers with concentrated positions in OLD SECOND BANCORP INC (OSBC).
This page ranks the largest institutional OSBC shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
Institutional Holders
183
Total Reported Value
$894.91M
Largest Holder
Blackrock, Inc.
Largest Position
$100.25M
Insider Transactions (90d)
12
Latest Filing Quarter
Q2 2026
New Institutional Positions
50
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Blackrock, Inc. | 0.00% | 4,298,683 | $100,245,292 | $111,378,877 | +$11,133,585 | +11.11% | |
| Dimensional Fund Advisors Lp | 0.01% | 2,498,671 | $58,268,836 | $64,740,566 | +$6,471,730 | +11.11% | |
| Vanguard Capital Management Llc | 0.00% | 2,179,877 | $50,834,732 | $56,480,613 | +$5,645,881 | +11.11% | |
| State Street Corp | 0.00% | 1,839,202 | $42,887,045 | $47,653,724 | +$4,766,679 | +11.11% | |
| Davis Asset Management, L.P. | 1.06% | 1,800,000 | $41,976,000 | $46,638,000 | +$4,662,000 | +11.11% | |
| American Century Companies Inc | 0.02% | 1,783,820 | $41,598,684 | $46,218,776 | +$4,620,092 | +11.11% | |
| Goldman Sachs Group Inc | 0.00% | 1,624,852 | $37,891,548 | $42,099,915 | +$4,208,367 | +11.11% | |
| Fj Capital Management Llc | 4.42% | 1,460,413 | $34,056,831 | $37,839,301 | +$3,782,470 | +11.11% | |
| Boston Partners | 0.03% | 1,415,165 | $32,924,716 | $36,666,925 | +$3,742,209 | +11.37% | |
| Geode Capital Management, Llc | 0.00% | 1,349,432 | $31,474,650 | $34,963,783 | +$3,489,133 | +11.09% | |
| Kennedy Capital Management Llc | 0.51% | 1,236,983 | $28,846,444 | $32,050,230 | +$3,203,786 | +11.11% | |
| Banc Funds Co Llc | 3.98% | 1,034,143 | $24,116,215 | $26,794,645 | +$2,678,430 | +11.11% | |
| Manufacturers Life Insurance Company, The | 0.02% | 872,651 | $20,350,221 | $22,610,387 | +$2,260,166 | +11.11% | |
| Vanguard Portfolio Management Llc | 0.00% | 819,368 | $19,107,662 | $21,229,825 | +$2,122,163 | +11.11% | |
| Stieven Capital Advisors, L.P. | 3.63% | 815,328 | $19,013,449 | $21,125,148 | +$2,111,699 | +11.11% | |
| River Street Advisors Llc | 5.35% | 779,008 | $18,166,456 | $20,184,097 | +$2,017,641 | +11.11% | |
| Northern Trust Corp | 0.00% | 555,408 | $12,952,115 | $14,390,621 | +$1,438,506 | +11.11% | |
| Alliancebernstein L.P. | 0.00% | 641,845 | $12,939,595 | $16,630,204 | +$3,690,609 | +28.52% | |
| Jpmorgan Chase & Co | 0.00% | 555,602 | $12,895,522 | $14,395,648 | +$1,500,126 | +11.63% | |
| Wellington Management Group Llp | 0.00% | 544,345 | $12,694,125 | $14,103,979 | +$1,409,854 | +11.11% | |
| Nuveen, Llc | 0.00% | 492,162 | $11,477,218 | $12,751,917 | +$1,274,699 | +11.11% | |
| Bridgeway Capital Management, Llc | 0.19% | 453,323 | $10,571,492 | $11,745,599 | +$1,174,107 | +11.11% | |
| Charles Schwab Investment Management Inc | 0.00% | 431,304 | $10,058,009 | $11,175,087 | +$1,117,078 | +11.11% | |
| Sixth Street Partners Management Company, L.P. | 0.00% | 431,304 | $10,058,009 | $11,175,087 | +$1,117,078 | +11.11% | |
| Aqr Capital Management Llc | 0.00% | 386,234 | $9,006,974 | $10,007,323 | +$1,000,349 | +11.11% | |
| Bank Of America Corp | 0.00% | 372,648 | $8,690,151 | $9,655,310 | +$965,159 | +11.11% | |
| Gator Capital Management, Llc | 1.81% | 359,730 | $8,388,904 | $9,320,604 | +$931,700 | +11.11% | |
| Bank Of New York Mellon Corp | 0.00% | 342,013 | $7,975,752 | $8,861,557 | +$885,805 | +11.11% | |
| Vanguard Fiduciary Trust Co | 0.00% | 341,200 | $7,956,784 | $8,840,492 | +$883,708 | +11.11% | |
| Congress Asset Management Co | 0.05% | 338,650 | $7,897,318 | $8,774,422 | +$877,104 | +11.11% | |
| Morgan Stanley | 0.00% | 318,318 | $7,423,207 | $8,247,619 | +$824,412 | +11.11% | |
| Citadel Advisors Llc | 0.00% | 304,021 | $7,089,770 | $7,877,184 | +$787,414 | +11.11% | |
| Mariner, Llc | 0.01% | 225,303 | $5,254,044 | $5,837,601 | +$583,557 | +11.11% | |
| Arrowstreet Capital, Limited Partnership | 0.00% | 210,745 | $4,914,573 | $5,460,403 | +$545,830 | +11.11% | |
| Forum Financial Management, Lp | 0.06% | 205,673 | $4,796,302 | $5,328,987 | +$532,685 | +11.11% | |
| Great Lakes Advisors, Llc | 0.04% | 203,909 | $4,755,158 | $5,283,282 | +$528,124 | +11.11% | |
| Empowered Funds, Llc | 0.03% | 233,559 | $4,708,549 | $6,051,514 | +$1,342,965 | +28.52% | |
| Two Sigma Investments, Lp | 0.00% | 200,819 | $4,683,099 | $5,203,220 | +$520,121 | +11.11% | |
| Squarepoint Ops Llc | 0.01% | 167,884 | $3,915,055 | $4,349,874 | +$434,819 | +11.11% | |
| Blair William & Co/Il | 0.01% | 163,228 | $3,806,470 | $4,229,237 | +$422,767 | +11.11% | |
| Siena Capital Partners Gp, Llc | 0.92% | 163,038 | $3,805,307 | $4,224,315 | +$419,008 | +11.01% | |
| Ejf Capital Lp | 2.36% | 151,358 | $3,529,669 | $3,921,686 | +$392,017 | +11.11% | |
| Ubs Group Ag | 0.00% | 147,223 | $3,433,240 | $3,814,548 | +$381,308 | +11.11% | |
| Victory Capital Management Inc | 0.00% | 141,914 | $3,309,434 | $3,676,992 | +$367,558 | +11.11% | |
| Russell Investments Group, Ltd. | 0.00% | 135,010 | $3,148,432 | $3,498,109 | +$349,677 | +11.11% | |
| Elizabeth Park Capital Advisors, Ltd. | 2.09% | 129,457 | $3,018,937 | $3,354,231 | +$335,294 | +11.11% | |
| Sei Investments Co | 0.00% | 117,666 | $2,743,974 | $3,048,726 | +$304,752 | +11.11% | |
| D. E. Shaw & Co., Inc. | 0.00% | 114,326 | $2,666,082 | $2,962,187 | +$296,105 | +11.11% | |
| Curi Capital, Llc | 0.04% | 100,505 | $2,343,777 | $2,604,085 | +$260,308 | +11.11% | |
| Swiss National Bank | 0.00% | 100,400 | $2,341,328 | $2,601,364 | +$260,036 | +11.11% |
Frequently asked questions about OSBC
Who owns the most OSBC stock?
The largest holders of OSBC are typically major institutional investors such as asset managers and hedge funds reporting on Form 13F. The table above ranks tracked superinvestors by reported position size using the latest available filings for OLD SECOND BANCORP INC (OSBC).
Is OSBC widely held by superinvestors?
Many widely followed stocks like OSBC appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly OSBC is represented among the institutional managers we track.
What do “Current Estimated Value”, “Gain/loss Since Filing”, and “Estimated Portfolio Performance” mean?
Current Estimated Value is reported share quantity from the latest 13F times our most recent split-adjusted U.S. session close. Gain/loss Since Filing is that estimate minus the reported 13F dollar value; Estimated Portfolio Performance is that difference as a percent of the reported value. Green means the estimate is above the filing value; red means below (not purchase cost). If many filers share the same implied filing price per share, the performance % may match across rows. These are not official fund marks or live quotes.