Old Second Bancorp, Inc.
US ˙ NasdaqGS ˙ US6802771005

SecurityOSBC / Old Second Bancorp, Inc.
InstitutionMillennium Management Llc
ManagerIsrael Englander
Latest Disclosed Ownership31,475 shares
Latest Disclosed Value $ 634,536
Millennium Management Llc reports 89.96% decrease in ownership of OSBC / Old Second Bancorp, Inc.

On May 15, 2026 - Millennium Management Llc filed a 13F-HR form disclosing ownership of 31,475 shares of Old Second Bancorp, Inc. (US:OSBC) valued at $634,536 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 313,560 shares of Old Second Bancorp, Inc.. This represents a change in shares of -89.96% during the quarter. The current value of the position is $678,601 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F OLD SECOND BANCORP INC DEL COM 680277100 31,475 -282,085 -89.96 635 -89.63 0.0003
2026-02-17 2025-12-31 13F OLD SECOND BANCORP INC ILL COM 680277100 313,560 313,560 6,114 0.0026
2025-11-14 2025-09-30 13F OLD SECOND BANCORP INC ILL COM 680277100 0 -57,426 -100.00 0 -100.00
2025-08-14 2025-06-30 13F OLD SECOND BANCORP INC ILL COM 680277100 57,426 -225,011 -79.67 1,019 -78.34 0.0005
2025-05-15 2025-03-31 13F OLD SECOND BANCORP INC ILL COM 680277100 282,437 -25,786 -8.37 4,700 -14.25 0.0025
2025-02-14 2024-12-31 13F OLD SECOND BANCORP INC ILL COM 680277100 308,223 252,430 452.44 5,480 530.61 0.0027
2024-11-14 2024-09-30 13F OLD SECOND BANCORP INC ILL COM 680277100 55,793 -52,309 -48.39 870 -45.69 0.0004
2024-08-14 2024-06-30 13F OLD SECOND BANCORP INC ILL COM 680277100 108,102 108,102 1,601 0.0007
2024-05-15 2024-03-31 13F OLD SECOND BANCORP INC ILL COM 680277100 0 -44,178 -100.00 0 -100.00
2024-02-14 2023-12-31 13F OLD SECOND BANCORP INC ILL COM 680277100 44,178 7,868 21.67 682 38.06 0.0003
2023-11-14 2023-09-30 13F OLD SECOND BANCORP INC ILL COM 680277100 36,310 36,310 494 0.0002
2023-08-14 2023-06-30 13F OLD SECOND BANCORP INC ILL COM 680277100 0 -75,721 -100.00 0 -100.00
2023-05-15 2023-03-31 13F OLD SECOND BANCORP INC ILL COM 680277100 75,721 -73,864 -49.38 1,065 -55.61 0.0006
2023-02-14 2022-12-31 13F OLD SECOND BANCORP INC ILL COM 680277100 149,585 -94,570 -38.73 2,399 -24.70 0.0013
2022-11-14 2022-09-30 13F OLD SECOND BANCORP INC ILL COM 680277100 244,155 129,565 113.07 3,186 107.83 0.0019
2022-08-15 2022-06-30 13F OLD SECOND BANCORP INC ILL COM 680277100 114,590 85,380 292.30 1,533 261.56 0.0010
2022-05-16 2022-03-31 13F OLD SECOND BANCORP INC ILL COM 680277100 29,210 -8,449 -22.44 424 -10.55 0.0002
2022-02-14 2021-12-31 13F OLD SECOND BANCORP INC ILL COM 680277100 37,659 -14,327 -27.56 474 -30.19 0.0002
2021-11-15 2021-09-30 13F OLD SECOND BANCORP INC ILL COM 680277100 51,986 -35,042 -40.27 679 -37.07 0.0004
2021-08-16 2021-06-30 13F OLD SECOND BANCORP INC ILL COM 680277100 87,028 87,028 1,079 0.0007
2021-05-17 2021-03-31 13F OLD SECOND BANCORP INC ILL COM 680277100 0 -35,269 -100.00 0 -100.00
2021-02-16 2020-12-31 13F OLD SECOND BANCORP INC ILL COM 680277100 35,269 35,269 356 0.0003
2020-11-16 2020-09-30 13F OLD SECOND BANCORP INC ILL COM 680277100 0 -60,816 -100.00 0 -100.00
2020-08-14 2020-06-30 13F OLD SECOND BANCORP INC ILL COM 680277100 60,816 60,816 473 0.0006
2020-05-14 2020-03-31 13F OLD SECOND BANCORP INC ILL COM 680277100 0 -105,660 -100.00 0 -100.00
2020-02-14 2019-12-31 13F OLD SECOND BANCORP INC ILL COM 680277100 105,660 62,742 146.19 1,423 171.56 0.0018
2019-11-14 2019-09-30 13F OLD SECOND BANCORP INC ILL COM 680277100 42,918 15,914 58.93 524 51.88 0.0008
2019-08-15 2019-06-30 13F/A-1 OLD SECOND BANCORP INC ILL COM 680277100 27,004 12,198 82.39 345 85.48 0.0005
2019-08-14 2019-06-30 13F ODONATE THERAPEUTICS COM 680277100 10,226 -4,580 375
2019-05-14 2019-03-31 13F OLD SECOND BANCORP INC ILL COM 680277100 14,806 14,806 -45.17 186 -46.09 0.0003
2019-02-15 2018-12-31 13F/A-1 OLD SECOND BANCORP INC ILL COM 680277100 0 -57,817 -100.00 0 -100.00
2018-11-14 2018-09-30 13F OLD SECOND BANCORP INC ILL COM 680277100 57,817 -80,417 -58.17 893 -55.15 0.0011
2018-08-14 2018-06-30 13F OLD SECOND BANCORP INC ILL COM 680277100 138,234 -32,955 -19.25 1,991 -16.34 0.0026
2018-05-15 2018-03-31 13F OLD SECOND BANCORP INC ILL COM 680277100 171,189 -159,589 -48.25 2,380 -47.29 0.0032
2018-02-14 2017-12-31 13F OLD SECOND BANCORP INC ILL COM 680277100 330,778 85,576 34.90 4,515 36.90 0.0062
2017-11-14 2017-09-30 13F OLD SECOND BANCORP INC ILL COM 680277100 245,202 8,664 3.66 3,298 20.72 0.0050
2017-08-14 2017-06-30 13F OLD SECOND BANCORP INC ILL COM 680277100 236,538 59,382 33.52 2,732 37.08 0.0049
2017-05-15 2017-03-31 13F OLD SECOND BANCORP INC ILL COM 680277100 177,156 50,171 39.51 1,993 42.05 0.0037
2017-02-14 2016-12-31 13F OLD SECOND BANCORP INC ILL COM 680277100 126,985 82,483 185.35 1,403 279.19 0.0029
2016-11-14 2016-09-30 13F OLD SECOND BANCORP INC ILL COM 680277100 44,502 44,502 -64.95 370 -73.63 0.0006
2016-08-15 2016-06-30 13F OLD SECOND BANCORP INC ILL COM 680277100 0 -15,987 -100.00 0 -100.00
2016-05-16 2016-03-31 13F OLD SECOND BANCORP INC ILL COM 680277100 15,987 -42,311 -72.58 115 -74.84 0.0003
2016-02-16 2015-12-31 13F OLD SECOND BANCORP INC ILL COM 680277100 58,298 47,171 423.93 457 562.32 0.0010
2015-11-16 2015-09-30 13F OLD SECOND BANCORP INC ILL COM 680277100 11,127 11,127 -80.91 69 -84.90 0.0001
2014-11-14 2014-09-30 13F OLD SECOND BANCORP INC ILL COM 680277100 0 -54,473 -100.00 0 -100.00
2014-08-14 2014-06-30 13F OLD SECOND BANCORP INC ILL COM 680277100 54,473 54,473 271 0.0008
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.