<SEC-DOCUMENT>0001104659-21-127505-index.html : 20211119
<SEC-HEADER>0001104659-21-127505.hdr.sgml : 20211119
<ACCEPTANCE-DATETIME>20211019134108
<PRIVATE-TO-PUBLIC>
ACCESSION NUMBER:		0001104659-21-127505
CONFORMED SUBMISSION TYPE:	CORRESP
PUBLIC DOCUMENT COUNT:		2
FILED AS OF DATE:		20211019

FILER:

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

	FILING VALUES:
		FORM TYPE:		CORRESP

	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>CORRESP
<SEQUENCE>1
<FILENAME>filename1.htm
<TEXT>
Document 1 - file: filename1.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>2
<FILENAME>tm2125387d5_correspimg001.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 2 - file: tm2125387d5_correspimg001.jpg

</DOCUMENT>
</SEC-DOCUMENT>