<SEC-DOCUMENT>0001104659-25-046065-index.html : 20250508
<SEC-HEADER>0001104659-25-046065.hdr.sgml : 20250508
<ACCEPTANCE-DATETIME>20250508152641
ACCESSION NUMBER:		0001104659-25-046065
CONFORMED SUBMISSION TYPE:	424B3
PUBLIC DOCUMENT COUNT:		5
FILED AS OF DATE:		20250508
DATE AS OF CHANGE:		20250508

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			OLD SECOND BANCORP INC
		CENTRAL INDEX KEY:			0000357173
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		ORGANIZATION NAME:           	02 Finance
		EIN:				363143493
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		424B3
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	333-286687
		FILM NUMBER:		25925581

	BUSINESS ADDRESS:	
		STREET 1:		37 S RIVER ST
		CITY:			AURORA
		STATE:			IL
		ZIP:			60507
		BUSINESS PHONE:		6308920202

	MAIL ADDRESS:	
		STREET 1:		37 SOUTH RIVER STREET
		CITY:			AURORA
		STATE:			IL
		ZIP:			60507
</SEC-HEADER>
<DOCUMENT>
<TYPE>424B3
<SEQUENCE>1
<FILENAME>tm2511100-6_424b3.htm
<DESCRIPTION>424B3
<TEXT>
Document 1 - file: tm2511100-6_424b3.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>2
<FILENAME>lg_oldsecondbancorp-4c.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 2 - file: lg_oldsecondbancorp-4c.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>3
<FILENAME>lg_bancorpfinancial-4clr.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 3 - file: lg_bancorpfinancial-4clr.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>4
<FILENAME>lg_rsm-4c.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 4 - file: lg_rsm-4c.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>5
<FILENAME>lg_kbw-4c.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 5 - file: lg_kbw-4c.jpg

</DOCUMENT>
</SEC-DOCUMENT>