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                          October 6, 2021

       James L. Eccher
       Chief Executive Officer
       Old Second Bancorp, Inc.
       37 South River Street
       Aurora, IL 60507

                                                        Re: Old Second Bancorp,
Inc.
                                                            Registration
Statement on Form S-4
                                                            Filed October 1,
2021
                                                            File No. 333-259964

       Dear Mr. Eccher:

              This is to advise you that we have not reviewed and will not
review your registration
       statement.

               Please refer to Rules 460 and 461 regarding requests for
acceleration. We remind you
       that the company and its management are responsible for the accuracy and
adequacy of their
       disclosures, notwithstanding any review, comments, action or absence of
action by the staff.

                                                        Please contact Tonya K.
Aldave at (202) 551-3601 with any questions.




                          Sincerely,


                          Division of Corporation Finance

                          Office of Finance
       cc:                                              Brennan Ryan, Esq.