Form 8-K

8-K — OLD SECOND BANCORP INC

Accession: 0000357173-26-000042

Filed: 2026-07-22

Period: 2026-07-22

CIK: 0000357173

SIC: 6022 (STATE COMMERCIAL BANKS)

Item: Results of Operations and Financial Condition

Item: Financial Statements and Exhibits

Documents

8-K — osbc-20260722x8k.htm (Primary)

EX-99.1 (osbc-20260722xex99d1.htm)

EX-99.2 (osbc-20260722xex99d2.htm)

GRAPHIC (osbc-20260722x8k001.jpg)

GRAPHIC (osbc-20260722xex99d1001.jpg)

GRAPHIC (osbc-20260722xex99d2g001.jpg)

GRAPHIC (osbc-20260722xex99d2g002.jpg)

GRAPHIC (osbc-20260722xex99d2g003.jpg)

GRAPHIC (osbc-20260722xex99d2g004.jpg)

GRAPHIC (osbc-20260722xex99d2g005.jpg)

GRAPHIC (osbc-20260722xex99d2g006.jpg)

GRAPHIC (osbc-20260722xex99d2g007.jpg)

GRAPHIC (osbc-20260722xex99d2g008.jpg)

GRAPHIC (osbc-20260722xex99d2g009.jpg)

GRAPHIC (osbc-20260722xex99d2g010.jpg)

XML — IDEA: XBRL DOCUMENT (R1.htm)

8-K

8-K (Primary)

Filename: osbc-20260722x8k.htm · Sequence: 1

OLD SECOND BANCORP INC_July 22, 2026

OLD SECOND BANCORP INC0000357173false00003571732026-07-222026-07-22

United States

Securities And Exchange Commission

Washington, D.C. 20549

FORM 8-K

Current Report

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): July 22, 2026

(Exact name of registrant as specified in its charter)

Delaware

000-10537

36-3143493

(State or other jurisdiction of incorporation)

(Commission File Number)

(I.R.S. Employer Identification No.)

37 South River Street

Aurora, Illinois 60507

(Address of principal executive offices) (Zip code)

(630) 892-0202

(Registrant’s telephone number, including area code)

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Common Stock

OSBC

The Nasdaq Stock Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 under the Securities Act (17 CFR 230.405) or Rule 12b-2 under the Exchange Act (17 CFR 240.12b-2).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 Results of Operations and Financial Condition

On July 22, 2026, Old Second Bancorp, Inc. (the “Company’s”) issued a press release announcing its financial results for the second quarter ended June 30, 2026, along with certain other financial information. Copies of the Company’s press release and loan portfolio disclosures are attached as Exhibits 99.1 and 99.2, respectively.

Item 9.01 Financial Statements and Exhibits

Exhibit No.

Description

99.1

Press Release of Old Second Bancorp, Inc. dated July 22, 2026

99.2

Loan Portfolio Disclosures for Old Second Bancorp, Inc. dated June 30, 2026

104

Cover Page Interactive Data File (the cover page XBRL tags are embedded within the Inline XBRL document)

Signature

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

OLD SECOND BANCORP, INC.

Dated: July 22, 2026

By:

/s/ Bradley S. Adams

Bradley S. Adams

Executive Vice President,

Chief Operating Officer and

Chief Financial Officer

EX-99.1

Filename: osbc-20260722xex99d1.htm · Sequence: 2

Old Second Bancorp, Inc

(NASDAQ:OSBC)

Exhibit 99.1

Contact:

Bradley S. Adams

For Immediate Release

Chief Financial Officer

July 22, 2026

(630) 906-5484

Old Second Bancorp, Inc. Reports Second Quarter 2026 Net Income of $28.2 Million,

or $0.54 per Diluted Share

AURORA, IL, July 22, 2026 – Old Second Bancorp, Inc. (the “Company,” “Old Second,” “we,” “us,” and “our”) (NASDAQ: OSBC), the parent company of Old Second National Bank (the “Bank”), today announced financial results for the second quarter of 2026. Our net income was $28.2 million, or $0.54 per diluted share, for the second quarter of 2026, compared to net income of $25.6 million, or $0.48 per diluted share, for the first quarter of 2026. Adjusted net income1 was $28.7 million, or adjusted diluted earnings per share1 of $0.55, for the second quarter of 2026, compared to adjusted net income1 of $26.0 million, or adjusted diluted earnings per share1 of $0.49, for the first quarter of 2026.

Notable Items2

● Net interest and dividend income was $83.3 million, reflecting an increase of $2.2 million, or 2.69%.

● Net interest margin (NIM) on a fully tax-equivalent basis1 was 5.23%, an increase of nine basis points.

● Provision for credit losses of $7.5 million compared to $9.5 million, a decrease of $2.0 million.

● Noninterest income was $13.3 million, an increase of $631,000, or 5.00%, compared to $12.6 million.

● Noninterest expense was $51.3 million, an increase of $1.0 million, or 2.08%, compared to $50.2 million.

● Efficiency ratio decreased 68 basis points to 51.72%; adjusted efficiency ratio was 50.80%1.

● Provision for income tax of $9.7 million, compared to $8.5 million, with an effective tax rate of 25.53% and 24.89%, respectively.

● Return on average assets of 1.65%, compared to 1.51%.

● Return on tangible common equity (ROATCE)1 of 15.58%; adjusted ROATCE1 of 15.85%.

● On July 21, 2026, our Board of Directors declared a cash dividend of $0.07 per share of common stock, payable on August 10, 2026, to stockholders of record as of July 31, 2026.

Chairman, President and Chief Executive Officer Jim Eccher said, “Old Second reported strong results in the second quarter of 2026 led by exceptional revenue and margin performance and disciplined operating efficiency. Tangible book value per share exhibited double-digit percentage growth on an annualized basis despite the repurchase of 732,000 shares during the quarter. Nonperforming, classified and criticized assets all decreased meaningfully during the second quarter, and we believe we are adequately reserved for any future losses with an Allowance for Credit Losses on loans (“ACL”) to total loans of 1.34% and ACL to nonperforming loans of 124.60%. Charge-offs in the second quarter largely resulted from one downtown Chicago office credit and one cash-flow-dependent commercial relationship which had been downgraded in prior quarters. Overall results are exceptionally strong across the board, despite a relatively elevated level of net charge-offs, with second quarter return on average assets and return on average tangible common equity of 1.65% and 15.58%, respectively. The tax equivalent net interest margin expanded nine basis points quarter over linked quarter to 5.23% and the efficiency ratio was a very healthy 51.72%. This strong bottom-line performance and a well-positioned balance sheet drove an increase in the tangible common equity capital ratio to 11.19% from 11.07% for the prior linked period. We are proud of our performance both from a bottom-line perspective and in positioning ourselves to deliver even better results to our stockholders over the last half of the year.”

1 Non-GAAP financial measure that management believes is useful in evaluating the financial results of the Company – refer to the non-GAAP reconciliation contained in this release.

2 All comparisons throughout this release are on a linked-quarter basis, unless otherwise noted.

Results of Operations:

Our net income was $28.2 million, or $0.54 per diluted share, for the second quarter of 2026, compared to net income of $25.6 million, or $0.48 per diluted share.

Loans increased $60.6 million driven primarily by increases in commercial, construction, multifamily, powersport, and other, including consumer.

● Total loans were $5.25 billion.

● Average loans (including loans held-for-sale) for the second quarter of 2026 totaled $5.22 billion, reflecting an increase of $15.3 million.

Credit Quality key performance metrics were impacted by two larger credits.

● Nonperforming loans totaled $56.5 million compared to $75.5 million. The $19.0 million decrease reflects paydowns, upgrades to performing status, loan payoffs, the renewal of $8.7 million of loans past due 90 days accruing that were in the process of renewal, and charge-offs of $5.8 million.

● Nonperforming loans to total loans was 1.08% compared to 1.46%.

● Classified loans totaled $132.1 million compared to $148.6 million.

● Criticized loans (special mention, substandard and doubtful) to total loans was 3.05% compared to 3.64%. The quarter-over-quarter decrease is driven by a decrease of $12.4 million in special mention loans, a decrease of $8.9 million of nonaccrual loans, and a decrease of $7.6 million in substandard accruing.

● Provision for credit losses of $7.5 million was driven by powersport charge-offs, and larger than normal charge-offs in commercial and commercial real estate; the non-powersport charge-offs were primarily isolated to two loan relationships.

Deposits experienced seasonal declines in savings and money market accounts as well as declines in time deposits as higher rate brokered deposits and other exception-priced time deposits assumed from Bancorp Financial, Inc. rolled off.

● Total deposits were $5.44 billion, a decrease of $120.3 million, or 2.16%.

● Cost of deposits decreased five basis points to 1.00%.

● Average interest-bearing deposits decreased $81.7 million while non-interest bearing deposits increased $7.0 million.

Net Interest Margin continued to be strong and increases in the cost of funds were outweighed by stronger yields during the quarter.

● Net interest margin on a fully tax-equivalent basis improved nine basis points.

● Loan yields increased 12 basis points on higher average loan balances during the quarter, and investment yields increased six basis points driven by maturities and paydowns of lower yielding securities.

● Cost of funds increased two basis points driven by higher costs on the remaining subordinated debt, coupled with $213,000 of accelerated issuance costs related to our partial redemption of $30.0 million of the original $60.0 million of subordinated debt during the quarter. Cost of deposits decreased by five basis points, specifically due to an 18-basis point decline in the cost of time deposits.

Noninterest Income increased $631,000, or 5.00%, in the second quarter of 2026.

● Wealth management related income increased in the period due to growth in advisory, insurance – annuities, agent, estate, and personal trust fees.

● The cash surrender value of BOLI increased in the current quarter due to market rate changes.

● Card related income increased in the current quarter due to growth in debit card related fees from higher transaction volumes.

● Other income decreased in the period due to a decrease in powersport related dealer charge-back income.

Noninterest Expense increased $1.0 million or 2.08%.

● Salaries and employee benefits increased $430,000, driven by growth in salaries, officer incentive accruals, deferred compensation expense, and insurance premiums, partially offset by decreases in payroll taxes and 401K company match as 2025 incentive payments were paid in the prior quarter.

● Other expenses increased $712,000 primarily due to growth in director deferred compensation expense, a $172,000 increase in litigation expense primarily regarding two unrelated customer disputes with limited exposure that are both considered non-recurring in nature, and an accrual of $184,000 related to powersport loan gap insurance refunds due to customers related to loan prepayments.

● Efficiency ratio for the quarter was 51.72% compared to 52.40% and the adjusted efficiency ratio1 was 50.80% compared to 51.70%.

Capital continued to grow due to strong net income.

● Stockholders’ equity increased $9.5 million due to net income of $28.2 million, partially offset by $3.6 million of dividends declared and a $15.5 million increase in treasury stock from share repurchases and stock award vestings.

● Share repurchases of 732,183 shares at an average price paid per share of $21.08, for a total reduction to capital of $15.4 million, net of excise taxes.

● ROATCE1 was 15.58% compared to 14.20%.

● Tangible common equity to tangible assets1 was 11.19% compared to 11.07%.

1 Non-GAAP financial measure that management believes is useful in evaluating the financial results of the Company – refer to the non-GAAP reconciliation contained in this release.

Cautionary Note Regarding Forward-Looking Statements

This earnings release and statements by our management may contain forward-looking statements within the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as “should,” “anticipate,” “expect,” “estimate,” “intend,” “believe,” “may,” “likely,” “will,” “forecast,” “project,” “looking forward,” “optimistic,” “hopeful,” “potential,” “progress,” “prospect,” “remain,” “deliver,” “continue,” “trend,” “momentum,” “remainder,” “beyond,” “build,” and “near” or other statements that indicate future events or expectations. Examples of forward-looking statements include, but are not limited to, statements regarding the economic outlook, balance sheet growth, and building capital. Such forward-looking statements are subject to risks, uncertainties, and other factors, which could cause actual results to differ materially from future results expressed or implied by such forward-looking statements. The following factors, among others, could cause actual results to differ materially from the anticipated results or other expectations expressed in the forward-looking statements:

● the strength of the United States economy in general and the strength of the local economies in which we conduct our operations may be different than expected;

● the rate of delinquencies and amounts of charge-offs, the level of allowance for credit loss, the rates of loan growth, or adverse changes in asset quality in our loan portfolio, which may result in increased credit risk-related losses and expenses;

● adverse developments in the commercial real estate market, including increased vacancy rates, declining property values, or borrower distress, particularly in the office sector, which could result in increased credit losses or require additional provisions;

● changes in legislation, regulation, policies, or administrative practices, whether by judicial, governmental, or legislative action;

● risks related to pending or future acquisitions, if any, including execution and integration risks;

● adverse conditions in the stock market, the public debt market and other capital markets (including changes in interest rate conditions) could have a negative impact on us;

● changes in interest rates, which have affected and may continue to affect our deposit and funding costs, net income, prepayment penalty income, mortgage banking income, and other future cash flows, or the market value of our assets, including our investment securities;

● elevated inflation which causes adverse risk to the overall economy, and could indirectly pose challenges to our clients and to our business; and

● the adverse effects of events beyond our control that may have a destabilizing effect on financial markets and the economy, such as trade disputes, epidemics and pandemics, war or terrorist activities, essential utility outages, deterioration in the global economy, instability in the credit markets, disruptions in our customers’ supply chains or disruptions in transportation, and disruptions caused by widespread cybersecurity incidents.

Additional risks and uncertainties are contained in the “Risk Factors” and forward-looking statements disclosure in our most recent Annual Report on Form 10-K, and Quarterly Reports on Form 10-Q. The inclusion of this forward-looking information should not be construed as a representation by us or any person that future events, plans, or expectations contemplated by us will be achieved. We undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise, except as required by law.

Conference Call

We will host a call on Thursday, July 23, 2026, at 10:00 a.m. Eastern Time (9:00 a.m. Central Time) to discuss our second quarter 2026 financial results. Investors may listen to our earnings call via a live webcast by accessing the link provided below, or alternatively, on the Events section of the Old Second Investor Relations website (https://investors.oldsecond.com/events). Investors are encouraged to register at the webcast link at least 10 minutes prior to the scheduled start of the call.

Webcast URL: https://www.webcaster5.com/Webcast/Page/2239/54212

A replay of the webcast will be available under the Events section of the Old Second Investor Relations website (https://investors.oldsecond.com/events) for up to one year after the earnings call date.

Non-GAAP Presentations

We consider the use of select non-GAAP financial measures and ratios to be useful for financial and operational decision-making and useful in evaluating period-to-period comparisons. We believe that these non-GAAP financial measures provide meaningful supplemental information regarding our performance by excluding certain expenditures or assets or by adjusting certain items that we believe are not indicative of our primary business operating results or by presenting certain metrics on a fully tax-equivalent basis. We believe these measures provide investors with information regarding balance sheet profitability, and we believe that management and investors benefit from referring to these non-GAAP financial measures in assessing our performance and when planning, forecasting, analyzing, and comparing past, present and future periods.

These non-GAAP financial measures should not be considered as a substitute for GAAP financial measures, and we strongly encourage investors to review the GAAP financial measures included in this earnings release and not to place undue reliance upon any single financial measure. In addition, because non-GAAP financial measures are not standardized, it may not be possible to compare the non-GAAP financial measures presented in this earnings release with other companies’ non-GAAP financial measures having the same or similar names. The tables beginning on page 12 provide a reconciliation of each non-GAAP financial measure to the most comparable GAAP equivalent.

Management has disclosed in this earnings release certain non-GAAP financial measures to evaluate and measure our performance, including the presentation of adjusted net income, net interest income and net interest margin on a fully tax-equivalent basis, and our efficiency ratio calculations on a tax-equivalent basis. The net interest margin on a fully tax-equivalent basis is calculated by dividing net interest income on a tax equivalent basis by average earning assets for the period. Consistent with industry practice, management has disclosed the efficiency ratio including and excluding certain items, which is discussed in the efficiency ratio presentation on page 13.

Financial Highlights

Quarters Ended

(Dollars in thousands - unaudited)

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Balance sheet summary

Total assets

6,870,305

6,849,221

6,902,675

6,991,754

5,701,294

Total securities available-for-sale

1,040,760

1,115,443

1,090,523

1,157,480

1,177,688

Total loans

5,245,870

5,185,237

5,252,131

5,264,505

3,998,667

Total deposits

5,444,688

5,564,999

5,596,069

5,760,250

4,798,439

Total liabilities

5,967,494

5,955,924

6,005,907

6,125,069

4,982,645

Total equity

902,811

893,297

896,768

866,685

718,649

Total tangible assets

6,719,760

6,697,509

6,749,787

6,836,565

5,588,090

Total tangible equity

752,266

741,585

743,880

711,496

605,445

Income statement summary

Net interest income

83,329

81,144

83,051

82,775

64,234

Provision for credit losses

7,500

9,500

3,000

19,653

2,500

Noninterest income

13,261

12,630

12,154

13,109

10,898

Noninterest expense

51,252

50,210

52,935

63,163

43,419

Net income

28,179

25,585

28,787

9,871

21,822

Effective tax rate

25.53

24.89

26.69

24.46

25.30

Profitability ratios

Return on average assets (ROAA)

1.65

1.51

1.64

0.56

1.53

Return on average equity (ROAE)

12.57

11.43

12.92

4.61

12.39

Net interest margin (tax-equivalent) 1

5.23

5.14

5.09

5.05

4.85

Efficiency ratio

51.72

52.40

53.98

64.46

55.99

Return on average tangible common equity (ROATCE) 1

15.58

14.20

16.15

6.16

15.29

Tangible common equity to tangible assets (TCE/TA) 1

11.19

11.07

11.02

10.41

10.83

Per share data

Diluted earnings per share

0.54

0.48

0.54

0.18

0.48

Tangible book value per share

14.77

14.35

14.12

13.51

13.44

Company capital ratios 2

Common equity tier 1 capital ratio

13.28

13.13

12.99

12.44

13.77

Tier 1 risk-based capital ratio

13.70

13.55

13.41

12.85

14.31

Total risk-based capital ratio

15.26

15.64

15.46

15.10

16.55

Tier 1 leverage ratio

12.05

11.88

11.70

11.21

11.83

Bank capital ratios 2, 3

Common equity tier 1 capital ratio

13.72

13.80

13.17

13.14

14.02

Tier 1 risk-based capital ratio

13.72

13.80

13.17

13.14

14.02

Total risk-based capital ratio

14.77

14.88

14.22

14.39

14.99

Tier 1 leverage ratio

12.05

12.09

11.49

11.45

11.59

1 See the discussion entitled “Non-GAAP Presentations” above and the table on pages 12 and 14 that provide a reconciliation of this non-GAAP financial measure to the most comparable GAAP equivalent.

2 Both the Company and the Bank ratios are inclusive of a capital conservation buffer of 2.50%, and both are subject to the minimum capital adequacy guidelines of 7.00%, 8.50%, 10.50%, and 4.00% for the Common equity tier 1, Tier 1 risk-based, Total risk-based and Tier 1 leverage ratios, respectively.

3 The prompt corrective action provisions are applicable only at the Bank level, and are 6.50%, 8.00%, 10.00%, and 5.00% for the Common equity tier 1, Tier 1 risk-based, Total risk-based and Tier 1 leverage ratios, respectively.

Old Second Bancorp, Inc. and Subsidiaries

Consolidated Balance Sheets

(In thousands - unaudited)

Quarters Ended

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Assets

Cash and due from banks

47,964

48,100

51,665

53,099

63,484

Interest earning deposits with financial institutions

95,369

67,627

72,360

63,426

78,283

Cash and cash equivalents

143,333

115,727

124,025

116,525

141,767

Securities available-for-sale, at fair value

1,040,760

1,115,443

1,090,523

1,157,480

1,177,688

Federal Home Loan Bank Chicago (“FHLBC”) and Federal Reserve Bank Chicago (“FRBC”) stock

40,125

31,350

32,025

28,282

19,087

Loans held-for-sale

2,349

4,344

3,645

1,463

3,235

Loans

5,245,870

5,185,237

5,252,131

5,264,505

3,998,667

Less: allowance for credit losses on loans

70,380

72,126

72,301

75,037

42,990

Net loans

5,175,490

5,113,111

5,179,830

5,189,468

3,955,677

Premises and equipment, net

84,505

85,634

86,645

87,714

85,702

Other real estate owned, net

622

632

1,427

6,416

6,486

Mortgage servicing rights, at fair value

9,825

9,579

9,459

9,549

9,680

Goodwill

129,196

130,262

93,232

Core deposit intangible ("CDI")

21,349

22,516

23,692

24,927

19,972

Bank-owned life insurance (“BOLI”)

133,493

131,563

130,481

129,057

114,399

Deferred tax assets, net

28,689

31,321

31,276

33,374

20,395

Other assets

60,569

58,805

60,451

77,237

53,974

Total assets

6,870,305

6,849,221

6,902,675

6,991,754

5,701,294

Liabilities

Deposits:

Noninterest bearing demand

1,746,755

1,755,548

1,739,117

1,738,028

1,704,083

Interest bearing:

Savings, NOW, and money market

2,771,532

2,795,038

2,745,540

2,763,990

2,400,235

Time

926,401

1,014,413

1,111,412

1,258,232

694,121

Total deposits

5,444,688

5,564,999

5,596,069

5,760,250

4,798,439

Securities sold under repurchase agreements

23,241

23,130

23,769

24,290

47,252

Other short-term borrowings

375,000

200,000

215,000

165,000

Junior subordinated debentures

25,774

Subordinated debentures

29,798

59,574

59,552

59,531

59,510

Notes payable and other borrowings

14,850

14,837

14,825

14,812

Other liabilities

54,143

67,610

70,918

75,412

51,670

Total liabilities

5,967,494

5,955,924

6,005,907

6,125,069

4,982,645

Stockholders’ Equity

Common stock

53,015

45,094

Additional paid-in capital

339,616

338,418

341,451

340,108

206,207

Retained earnings

583,701

559,129

537,231

512,131

505,419

Accumulated other comprehensive loss, net

(31,861)

(31,095)

(28,738)

(32,294)

(37,426)

Treasury stock

(41,660)

(26,170)

(6,191)

(6,275)

(645)

Total stockholders’ equity

902,811

893,297

896,768

866,685

718,649

Total liabilities and stockholders’ equity

6,870,305

6,849,221

6,902,675

6,991,754

5,701,294

Old Second Bancorp, Inc. and Subsidiaries

Consolidated Statements of Income

(In thousands, except share data - unaudited)

Three Months Ended

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Interest and dividend income

Loans, including fees

89,845

87,138

90,925

91,301

61,954

Loans held-for-sale

Securities:

Taxable

9,088

8,949

9,136

9,872

9,959

Tax exempt

1,132

1,155

1,219

1,235

1,229

Dividends from FHLBC and FRBC stock

535

512

390

381

273

Interest bearing deposits with financial institutions

527

549

598

1,255

1,784

Total interest and dividend income

101,189

98,346

102,303

104,075

75,238

Interest expense

Savings, NOW, and money market deposits

7,512

7,147

7,906

9,043

5,606

Time deposits

6,199

7,217

8,665

10,896

4,508

Securities sold under repurchase agreements

Other short-term borrowings

2,989

1,791

1,644

308

Junior subordinated debentures

289

296

288

Subordinated debentures

675

546

547

546

Notes payable and other borrowings

156

155

158

Total interest expense

17,860

17,202

19,252

21,300

11,004

Net interest and dividend income

83,329

81,144

83,051

82,775

64,234

Provision for credit losses

7,500

9,500

3,000

19,653

2,500

Net interest and dividend income after provision for credit losses

75,829

71,644

80,051

63,122

61,734

Noninterest income 1

Wealth management

3,628

3,383

3,537

3,515

3,103

Service charges on deposits

3,075

3,130

3,125

3,202

3,060

Secondary mortgage fees

166

121

123

Mortgage servicing rights mark to market loss

(152)

(428)

(389)

(531)

Mortgage servicing income

464

497

444

469

472

Net gain on sales of mortgage loans

640

555

657

620

550

Securities gains (losses), net

(1)

Change in cash surrender value of BOLI

1,469

1,082

834

1,175

690

Death benefit realized on BOLI

430

Card related income

2,483

2,350

2,548

2,581

2,533

Other income

1,488

1,664

1,306

1,415

937

Total noninterest income

13,261

12,630

12,154

13,109

10,898

Noninterest expense 1

Salaries and employee benefits

30,103

29,673

30,996

39,723

26,950

Occupancy, furniture and equipment

5,118

5,371

5,092

4,937

4,477

Computer and data processing

3,217

3,375

4,798

4,002

2,692

FDIC insurance

759

720

854

642

Net teller & bill paying

724

716

701

691

670

General bank insurance

351

353

354

437

328

Amortization of core deposit intangible

1,167

1,176

1,235

1,251

1,022

Advertising and marketing expense

483

551

437

650

454

Card related expense

1,604

1,519

1,652

1,708

1,489

Professional fees

1,160

1,299

1,265

3,145

1,158

Consumer credit expense

1,720

1,522

1,451

1,368

Other real estate expense, net

(186)

128

Other expense

4,794

4,082

4,153

4,269

3,487

Total noninterest expense

51,252

50,210

52,935

63,163

43,419

Income before income taxes

37,838

34,064

39,270

13,068

29,213

Provision for income taxes

9,659

8,479

10,483

3,197

7,391

Net income

28,179

25,585

28,787

9,871

21,822

Basic earnings per share

0.55

0.49

0.55

0.19

0.49

Diluted earnings per share

0.54

0.48

0.54

0.18

0.48

Dividends declared per share

0.07

0.06

Ending common shares outstanding

50,938,962

51,665,660

52,669,224

52,664,535

45,056,183

Weighted-average basic shares outstanding

51,250,245

52,450,306

52,667,899

52,686,391

45,053,650

Weighted-average diluted shares outstanding

52,120,337

53,303,072

53,480,431

53,509,690

45,839,465

1 Certain items in prior periods have been reclassified to conform to the current presentation.

Analysis of Average Balances,

Tax Equivalent Income / Expense and Rates

(Dollars in thousands - unaudited)

Quarters Ended

June 30, 2026

March 31, 2026

June 30, 2025

Average

Income /

Rate

Average

Income /

Rate

Average

Income /

Rate

Balance

Expense

Balance

Expense

Balance

Expense

Assets

Interest earning deposits with financial institutions

64,839

527

3.26

67,571

549

3.30

166,366

1,784

4.30

Securities:

Taxable

955,176

9,088

3.82

969,194

8,949

3.74

1,040,472

9,959

3.84

Non-taxable (TE)1

140,876

1,433

4.08

146,299

1,462

4.05

149,651

1,556

4.17

Total securities (TE)1

1,096,052

10,521

3.85

1,115,493

10,411

3.79

1,190,123

11,515

3.88

FHLBC and FRBC Stock

36,676

535

5.85

31,540

512

6.58

19,200

273

5.70

Loans and loans held-for-sale1, 2

5,223,093

89,921

6.91

5,207,744

87,194

6.79

3,960,650

62,002

6.28

Total interest earning assets

6,420,660

101,504

6.34

6,422,348

98,666

6.23

5,336,339

75,574

5.68

Cash and due from banks

46,700

48,252

47,875

Allowance for credit losses on loans

(72,418)

(71,869)

(41,544)

Other noninterest earning assets

457,995

460,433

394,034

Total assets

6,852,937

6,859,164

5,736,704

Liabilities and Stockholders' Equity

NOW accounts

717,468

897

0.50

697,692

823

0.48

653,334

681

0.42

Money market accounts

948,319

4,400

1.86

946,075

4,148

1.78

832,777

3,920

1.89

Savings accounts

1,109,381

2,215

0.80

1,118,979

2,176

0.79

938,836

1,005

0.43

Time deposits

968,464

6,199

2.57

1,062,623

7,217

2.75

695,946

4,508

2.60

Interest bearing deposits

3,743,632

13,711

1.47

3,825,369

14,364

1.52

3,120,893

10,114

1.30

Securities sold under repurchase agreements

21,337

0.75

24,795

0.82

35,419

0.63

Other short-term borrowings

312,803

2,989

3.83

189,056

1,791

3.84

Junior subordinated debentures

25,774

289

4.50

25,774

296

4.66

25,773

288

4.48

Subordinated debentures

34,373

675

7.88

59,564

546

3.72

59,500

546

3.68

Notes payable and other borrowings

14,844

156

4.22

14,831

155

4.24

Total interest bearing liabilities

4,152,763

17,860

1.73

4,139,389

17,202

1.69

3,241,585

11,004

1.36

Noninterest bearing deposits

1,745,475

1,738,504

1,729,287

Other liabilities

55,582

73,284

59,578

Stockholders' equity

899,117

907,987

706,254

Total liabilities and stockholders' equity

6,852,937

6,859,164

5,736,704

Net interest income (GAAP)

83,329

81,144

64,234

Net interest margin (GAAP)

5.21

5.12

4.83

Net interest income (TE)1

83,644

81,464

64,570

Net interest margin (TE)1

5.23

5.14

4.85

Interest bearing liabilities to earning assets

64.68

64.45

60.75

1 Tax equivalent (TE) basis is calculated using a marginal tax rate of 21% in 2026 and 2025. See the discussion entitled “Non-GAAP Presentations” above and the tables beginning on page 12 that provide a reconciliation of each non-GAAP measure to the most comparable GAAP equivalent.

2 Interest income from loans is shown on a TE basis, which is a non-GAAP financial measure as discussed in the table on page 12, and includes loan fee income of $2.0 million for the second quarter of 2026, loan fee income of $1.9 million for the first quarter of 2026, and loan fee income of $366,000 for the second quarter of 2025. Nonaccrual loans are included in the above stated average balances.

Loans and Credit Quality

Loans

Quarters Ended

(Dollars in thousands)

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Commercial

913,527

845,278

842,130

786,095

718,927

Leases

537,197

539,116

548,256

550,201

524,513

Commercial real estate – investor

1,159,168

1,169,318

1,212,384

1,257,328

1,118,782

Commercial real estate – owner occupied

667,645

702,986

706,567

680,412

652,449

Construction

153,553

143,563

173,630

176,387

251,692

Residential real estate – investor

65,133

69,763

70,225

69,362

50,976

Residential real estate – owner occupied

242,768

239,711

230,432

231,547

220,672

Multifamily

363,352

357,131

339,131

378,213

333,787

HELOC

239,307

235,637

235,293

234,885

111,265

Powersport

683,939

674,116

696,959

715,498

Other1

220,281

208,618

197,124

184,577

15,604

Total loans

5,245,870

5,185,237

5,252,131

5,264,505

3,998,667

1 The “Other” classification includes consumer loans, such as collector cars, manufactured homes, and solar loans, as well as overdrafts.

Nonperforming assets

Quarters Ended

(Dollars in thousands)

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Nonaccrual loans

53,747

62,636

47,952

34,126

31,902

Loans past due 90 days or more and still accruing interest

2,736

12,868

4,879

13,859

345

Total nonperforming loans

56,483

75,504

52,831

47,985

32,247

Other real estate owned

622

632

1,427

6,416

6,486

Repossessed assets 1

819

858

1,363

2,088

234

Total nonperforming assets

57,924

76,994

55,621

56,489

38,967

30-89 days past due loans and still accruing interest

22,499

50,036

52,169

22,415

14,652

Nonaccrual loans to total loans

1.02

1.21

0.91

0.65

0.80

Nonperforming loans to total loans

1.08

1.46

1.01

0.91

0.81

Nonperforming assets to total loans plus OREO and repossessed assets

1.10

1.48

1.06

1.07

0.97

Purchased credit-deteriorated loans to total loans

1.19

1.35

1.50

1.61

0.23

Allowance for credit losses

70,380

72,126

72,301

75,037

42,990

Allowance for credit losses to total loans

1.34

1.39

1.38

1.43

1.08

Allowance for credit losses to nonaccrual loans

130.95

115.15

150.78

219.88

134.76

1 Repossessed assets are reported in other assets.

The following table shows classified loans by segment, which include nonaccrual loans, purchased credit deteriorated (“PCD”) loans if the risk rating so indicates, and all other loans considered substandard, for the following periods.

Classified loans

Quarters Ended

(Dollars in thousands)

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Commercial

39,646

50,640

51,587

50,680

23,354

Leases

2,930

2,604

2,428

1,277

1,346

Commercial real estate – investor

11,262

14,959

14,245

2,853

14,752

Commercial real estate – owner occupied

58,582

60,594

64,081

72,020

51,335

Construction

12,976

12,983

11,421

1,612

1,624

Residential real estate – investor

662

1,012

1,142

1,228

1,201

Residential real estate – owner occupied

2,076

1,886

1,897

1,839

1,707

Multifamily

1,197

1,489

1,494

1,183

1,099

HELOC

2,250

1,832

1,466

1,538

1,180

Powersport

198

204

Other1

318

369

270

Total classified loans

132,097

148,572

150,099

134,260

97,620

1 The “Other” classification includes consumer loans, such as collector cars, manufactured homes, and solar loans, as well as overdrafts.

Loan charge–offs, net of recoveries

Quarters Ended

(Dollars in thousands)

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Commercial

2,983

1,298

(44)

385

1,093

Leases

344

197

848

(3)

Commercial real estate – Investor

2,804

3,919

(14)

(15)

(14)

Commercial real estate – Owner occupied

(1)

(5)

1,125

(2)

(1)

Construction

(46)

(337)

Residential real estate – Investor

(1)

(2)

(1)

(2)

Residential real estate – Owner occupied

(21)

(7)

(11)

(7)

(8)

Multifamily

181

HELOC

(14)

(6)

(49)

(19)

(10)

Powersport

2,826

3,894

4,466

2,980

Other 1

328

488

494

805

Net charge–offs / (recoveries)

9,248

9,776

5,981

5,108

785

1 The “Other” classification includes consumer loans, such as collector cars, manufactured homes, and solar loans, as well as overdrafts.

Old Second Bancorp, Inc. and Subsidiaries

Quarterly Consolidated Average Balance

(In thousands - unaudited)

Quarters Ended

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Assets

Cash and due from banks

46,700

48,252

52,040

51,357

47,875

Interest earning deposits with financial institutions

64,839

67,571

66,430

119,619

166,366

Cash and cash equivalents

111,539

115,823

118,470

170,976

214,241

Securities available-for-sale, at fair value

1,096,052

1,115,493

1,129,633

1,165,900

1,190,123

Federal Home Loan Bank Chicago (“FHLBC”) and Federal Reserve Bank Chicago (“FRBC”) stock

36,676

31,540

30,085

25,961

19,200

Loans held-for-sale

3,280

2,023

3,254

1,975

2,375

Loans

5,219,813

5,205,721

5,275,389

5,215,374

3,958,275

Less: allowance for credit losses on loans

72,418

71,869

73,718

72,354

41,544

Net loans

5,147,395

5,133,852

5,201,671

5,143,020

3,916,731

Premises and equipment, net

85,395

86,260

87,449

88,304

87,081

Other real estate owned, net

626

853

4,410

6,464

2,099

Mortgage servicing rights, at fair value

9,693

9,383

9,490

9,632

9,856

Goodwill

129,196

130,135

127,873

93,232

Core deposit intangible ("CDI")

21,916

23,073

24,281

25,539

20,462

Bank-owned life insurance (“BOLI”)

132,046

130,930

130,151

128,870

113,326

Deferred tax assets, net

31,296

30,342

32,705

30,375

23,549

Other assets

47,827

50,396

58,443

74,364

44,429

Total assets

6,852,937

6,859,164

6,960,177

6,999,253

5,736,704

Liabilities

Deposits:

Noninterest bearing demand

1,745,475

1,738,504

1,781,374

1,782,193

1,729,287

Interest bearing:

Savings, NOW, and money market

2,775,168

2,762,746

2,764,609

2,798,414

2,424,947

Time

968,464

1,062,623

1,179,966

1,347,455

695,946

Total deposits

5,489,107

5,563,873

5,725,949

5,928,062

4,850,180

Securities sold under repurchase agreements

21,337

24,795

23,464

33,382

35,419

Other short-term borrowings

312,803

189,056

159,565

25,978

Junior subordinated debentures

25,774

25,773

Subordinated debentures

34,373

59,564

59,542

59,521

59,500

Notes payable and other borrowings

14,844

14,831

14,819

14,806

Other liabilities

55,582

73,284

67,078

61,732

59,578

Total liabilities

5,953,820

5,951,177

6,076,191

6,149,255

5,030,450

Stockholders’ Equity

Common stock

53,015

45,094

Additional paid-in capital

339,145

340,459

340,870

339,612

205,706

Retained earnings

573,158

551,491

526,910

500,075

497,224

Accumulated other comprehensive loss, net

(31,113)

(26,361)

(30,594)

(36,823)

(41,080)

Treasury stock

(35,088)

(10,617)

(6,215)

(5,881)

(690)

Total stockholders’ equity

899,117

907,987

883,986

849,998

706,254

Total liabilities and stockholders’ equity

6,852,937

6,859,164

6,960,177

6,999,253

5,736,704

Total Earning Assets

6,420,660

6,422,348

6,504,791

6,528,829

5,336,339

Total Interest Bearing Liabilities

4,152,763

4,139,389

4,227,739

4,305,330

3,241,585

Reconciliation of Non-GAAP Financial Measures

The tables below provide a reconciliation of each non-GAAP financial measure to the most comparable GAAP measure for the periods indicated. Dollar amounts below in thousands:

Net Income and Earnings Per Share - GAAP and Adjusted

Three Months Ended

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Income before income taxes (GAAP)

37,838

34,064

39,270

13,068

29,213

Pre-tax income adjustments:

Provision for credit losses - Day Two

13,153

Securities (gains) losses, net

(8)

Death benefit related to BOLI

(430)

MSR losses

152

428

389

531

Acquisition related costs, net of (gains) losses on branch sales

526

349

2,296

11,508

810

Adjusted net income before taxes

38,516

34,565

41,986

37,689

30,554

Taxes on adjusted net income

9,832

8,604

11,208

9,326

7,730

Adjusted net income (non-GAAP)

28,684

25,961

30,778

28,363

22,824

Basic earnings per share (GAAP)

0.55

0.49

0.55

0.19

0.49

Diluted earnings per share (GAAP)

0.54

0.48

0.54

0.18

0.48

Adjusted basic earnings per share (non-GAAP)

0.56

0.49

0.59

0.54

0.50

Adjusted diluted earnings per share (non-GAAP)

0.55

0.49

0.58

0.53

0.50

Total average assets

6,852,937

6,859,164

6,960,177

6,999,253

5,736,704

Return on average assets (GAAP)

1.65

1.51

1.64

0.56

1.53

Adjusted return on average assets (non-GAAP)

1.68

1.53

1.75

1.61

1.60

Quarters Ended

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Net Interest Margin

Interest income (GAAP)

101,189

98,346

102,303

104,075

75,238

Taxable-equivalent adjustment:

Loans

Securities

301

307

324

328

327

Interest income (TE)

101,504

98,666

102,636

104,413

75,574

Interest expense (GAAP)

17,860

17,202

19,252

21,300

11,004

Net interest income (TE)

83,644

81,464

83,384

83,113

64,570

Net interest income (GAAP)

83,329

81,144

83,051

82,775

64,234

Average interest earning assets

6,420,660

6,422,348

6,504,791

6,528,829

5,336,339

Net interest margin (GAAP)

5.21

5.12

5.07

5.03

4.83

Net interest margin (TE)

5.23

5.14

5.09

5.05

4.85

GAAP

Three Months Ended

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Efficiency Ratio (GAAP)

Noninterest expense

51,252

50,210

52,935

63,163

43,419

Less amortization of core deposit

1,167

1,176

1,235

1,251

1,022

Less other real estate expense, net

(186)

128

Less acquisition related costs, net of losses (gains) on branch sales

N/A

Noninterest expense less adjustments

50,033

49,220

51,619

61,784

42,362

Net interest income

83,329

81,144

83,051

82,775

64,234

Taxable-equivalent adjustment:

Loans

N/A

Securities

N/A

Net interest income including adjustments

83,329

81,144

83,051

82,775

64,234

Noninterest income

13,261

12,630

12,154

13,109

10,898

Less death benefit related to BOLI

430

Less securities gains (losses)

(1)

Less MSRs mark to market (losses) gains

(152)

(428)

(389)

(531)

Taxable-equivalent adjustment:

Change in cash surrender value of BOLI

N/A

Noninterest income including adjustments

13,413

12,782

12,574

13,069

11,429

Net interest income including adjustments plus noninterest income including adjustments

96,742

93,926

95,625

95,844

75,663

Efficiency ratio (GAAP)

51.72

52.40

53.98

64.46

55.99

N/A - Not applicable.

Non-GAAP

Three Months Ended

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Adjusted Efficiency Ratio (non-GAAP)

Noninterest expense

51,252

50,210

52,935

63,163

43,419

Less amortization of core deposit

1,167

1,176

1,235

1,251

1,022

Less other real estate expense, net

(186)

128

Less acquisition related costs, net of losses (gains) on branch sales

526

349

2,296

11,508

810

Noninterest expense less adjustments

49,507

48,871

49,323

50,276

41,552

Net interest income

83,329

81,144

83,051

82,775

64,234

Taxable-equivalent adjustment:

Loans

Securities

301

307

324

328

327

Net interest income including adjustments

83,644

81,464

83,384

83,113

64,570

Noninterest income

13,261

12,630

12,154

13,109

10,898

Less death benefit related to BOLI

430

Less securities gains (losses)

(1)

Less MSRs mark to market (losses) gains

(152)

(428)

(389)

(531)

Taxable-equivalent adjustment:

Change in cash surrender value of BOLI

390

288

222

312

184

Noninterest income including adjustments

13,803

13,070

12,796

13,381

11,613

Net interest income including adjustments plus noninterest income including adjustments

97,447

94,534

96,180

96,494

76,183

Adjusted efficiency ratio (non-GAAP)

50.80

51.70

51.28

52.10

54.54

Quarters Ended

June 30,

March 31,

December 31,

September 30,

June 30,

2026

2025

Adjusted Return on Average Tangible Common Equity Ratio

Net income (GAAP)

28,179

25,585

28,787

9,871

21,822

Income before income taxes (GAAP)

37,838

34,064

39,270

13,068

29,213

Pre-tax income adjustments:

Provision for credit losses - Day Two

13,153

Securities (gains) losses, net

(8)

MSR losses

152

428

389

531

Merger-related costs, net of losses (gains) on branch sales

526

349

2,296

11,508

810

Death benefit realized on BOLI

(430)

Amortization of core deposit intangibles

1,167

1,176

1,235

1,251

1,022

Adjusted net income, excluding intangibles amortization, before taxes

39,683

35,741

43,221

38,940

31,576

Taxes on adjusted net income

10,130

8,896

11,538

9,632

7,989

Adjusted net income, excluding intangibles amortization (non-GAAP)

29,553

26,845

31,683

29,308

23,587

Total Average Common Equity

899,117

907,987

883,986

849,998

706,254

Less average goodwill and intangible assets

151,112

152,269

154,416

153,412

113,694

Average tangible common equity (non-GAAP)

748,005

755,718

729,570

696,586

592,560

Return on average common equity (GAAP)

12.57

11.43

12.92

4.61

12.39

Return on average tangible common equity (non-GAAP)

15.58

14.20

16.15

6.16

15.29

Adjusted return on average tangible common equity (non-GAAP)

15.85

14.41

17.23

16.69

15.97

EX-99.2

Filename: osbc-20260722xex99d2.htm · Sequence: 3

Loan Portfolio Disclosures

AS OF JUNE 30, 2026

Exhibit 99.2

Portfolio Segment Outstanding Classified Allowance

Commercial (incl. Leases) $1,451 $43 1.14%

Commercial Real Estate Investor $1,159 $11 1.66%

Commercial Real Estate Owner Occ. $668 $59 0.68%

Construction $154 $13 0.73%

Residential Real Estate $308 $3 0.67%

Multifamily $363 $1 0.41%

HELOC $239 $2 1.38%

Powersport $684 - 2.47%

Other $220 - 1.96%

Total $5,246 $132 1.34%

Construction

Commercial RE

Investor

22%

Commercial RE

Owner Occ.

13%

Commercial

(inc. Leases)

28%

Multifamily

Residential

Real Estate

HELOC

Other (less than

$100 million)

Powersport

13%

Loan Portfolio Composition (in millions)

Q2 2026 Loan Portfolio Disclosures

Total Loans and Allowance for Credit Losses Trend (in millions)

$3,981 $3,940 $3,999 $5,265 $5,252 $5,185 $5,246

$44 $42 $43

$75 $72 $72 $70

$10

$20

$30

$40

$50

$60

$70

$80

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

$7,000

12/31/2024 3/31/2025 6/30/2025 9/30/2025 12/31/2025 3/31/2026 6/30/2026

Total Loans ACL

Criticized Loans (in millions)

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

7.00%

8.00%

$50

$100

$150

$200

$250

$300

$350

9/30/22 12/31/22 3/31/23 6/30/23 9/30/23 12/31/23 3/31/24 6/30/24 9/30/24 12/31/24 3/31/25 6/30/25 9/30/25 12/31/25 3/31/26 3/31/26

Office CRE Healthcare Other Criticized Loans/ Total Loans

Q2 2026 Loan Portfolio Disclosures

$1,802

$4,988

$632 $622

$1,076

$1,498

$6,416

$1,427

$484

$234 $2,088

$1,363

$858 $819

$2,000

$4,000

$6,000

$8,000

$10,000

3/31/25 6/30/25 9/30/25 12/31/25 3/31/26 6/30/26

OREO OREO Under Contract Repossessed Assets

OREO and Repossessed Assets (in thousands)

Participation / Syndication Portfolio Mix (in millions)

Participation / Syndication Portfolio Exposure (in millions)

Parti / Syndi Portfolio Outstanding SNC Classified

Manufacturing C&I $72 - $8

Office CRE $27 - -

Construction $33 - -

Multifamily $26 - -

Hotel CRE $23 - -

Healthcare $16 - -

Other (under $15 million) $68 $9 -

Total Purchased $265 $9 $8 Manufacturing

C&I

27%

Office CRE

10%

Construction

12%

Multifamily

10%

Hotel CRE

Healthcare

Other (under

$15 million)

26%

$543 $463 $362 $285 $265

14.2%

11.1%

8.9%

4.5% 4.9%

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

$100

$200

$300

$400

$500

$600

12/31/2022 12/31/2023 12/31/2024 12/31/2025 6/30/2026

Outstanding % of Total Commitments

Q2 2026 Loan Portfolio Disclosures

Property Type Outstanding LTV Classified Allowance

Retail $338 53% $2 0.93%

Industrial $273 48% - 1.14%

Office $174 68% - 2.14%

Hotel $88 51% - 1.67%

Senior Living $78 58% - 1.04%

Parking Garage $76 49% - 0.86%

Other (under $50 million) $132 70% $9 4.77%

Total $1,159 56% $11 1.66%

Commercial Real Estate Investor Portfolio Composition (in millions)

Retail

29%

Office

15%

Industrial

23%

Parking Garage

Hotel

Senior Living

Other (under

$50 million)

11%

Illinois

55%

Wisconsin

Texas

North Carolina

Pennsylvania

Oklahoma

Other (under $30

million)

21%

State Outstanding LTV Classified

Illinois $633 60% $11

Wisconsin $85 58% -

Texas $79 55% -

North Carolina $49 49% -

Oklahoma $34 62% -

Pennsylvania $32 51% -

Florida $29 40% -

Other (under $25 million) $218 49% -

Total $1,159 56% $11

Q2 2026 Loan Portfolio Disclosures

Location Outstanding LTV Classified Allowance

Illinois $148 69% - 2.39%

Chicago $32 69% - 2.46%

Suburban $116 69% - 2.37%

Oklahoma $15 64% - 0.84%

Colorado $6 52% - 0.84%

Oregon $4 73% - 0.84%

Wisconsin $1 63% - 0.84%

Total $174 68% - 2.14%

Office Commercial Real Estate Investor Portfolio Composition (in millions)

Illinois - Chicago

18%

Illinois - Suburban

67%

Oklahoma

Other (less than

$5 million)

Colorado

Office Commercial Real Estate Investor Risk Profile (in millions)

Q2 2026 Loan Portfolio Disclosures

$50

$57

$30

$36

$20

$40

$60

< 1 year 1-3 years 3-5 years > 5 years

Maturity Outstanding LTV DSCR

< 1 year $46 69% 1.28x

1-3 years $54 56% 1.38x

3-5 years $22 62% 1.42x

> 5 years $35 54% 1.53x

Total $157 60% 1.39x

Office Commercial Real Estate by Loan Maturity Office Commercial Real Estate > $1 million

Industry Outstanding Classified Allowance

Health Care, Social Services $261 $27 0.86%

Other Services $80 $6 0.59%

Retail Trade $63 - 0.18%

Manufacturing $57 - 0.20%

Real Estate, Leasing $43 - 0.26%

Accommodation, Food Service $30 $7 1.64%

Wholesale Trade $28 $1 0.49%

Arts, Entertainment $22 $2 0.75%

Other (under $20 million) $84 $16 1.04%

Total $668 $59 0.68%

Manufacturing

Accommodation,

Food Service

Retail Trade

Real Estate,

Leasing

Healthcare

39%

Other Services

12%

Other (under $30

million)

20%

Commercial Real Estate Owner-Occupied Portfolio Composition (in millions)

Health Care, Social Outstanding Classified Allowance

Assisted Living $139 $26 1.28%

Skilled Nursing $53 - 0.19%

Memory Care $49 - 0.33%

Child Care $6 - 1.99%

Other (under $5 million) $14 $1 0.68%

Total $261 $27 0.86%

Skilled

Nursing

20%

Assisted

Living

53%

Memory Care

19%

Child Care

Other (under $5 million)

Q2 2026 Loan Portfolio Disclosures

Commercial & Industrial Outstanding Classified

Manufacturing $437 $9

Construction $228 $6

Administrative, Waste Service $160 $4

Professional $133 -

Transportation, Warehousing $102 $14

Finance, Insurance $91 -

Real Estate, Leasing $74 -

Health Care, Social Services $61 $1

Wholesale Trade $53 $3

Other (under $20 million) $112 $6

Total $1,451 $43

Commercial (including Leases) Portfolio Composition (in millions)

Construction

16%

Manufacturing

30%

Transportation,

Warehousing

Finance, Insurance

Professional

Administration,

Waste Service

11%

Health Care,

Social Services

Real Estate,

Leasing

Other (under

$60 million)

12%

Commercial Revolving Line Utilization (outstanding in millions)

$677 $653 $587 $574 $658 $717 $718 $756

56% 55%

52% 53%

55% 57% 57%

60%

30%

35%

40%

45%

50%

55%

60%

65%

70%

$400

$450

$500

$550

$600

$650

$700

$750

$800

9/30/24 12/31/24 3/31/25 6/30/25 9/30/25 12/31/25 3/31/26 6/30/26

Q2 2026 Loan Portfolio Disclosures

Origination Tier Outstanding Weighted FICO Portfolio APR %

Tier 1 $362 777 7.96%

Tier 2 $129 711 10.21%

Tier 3 $77 684 12.73%

Tier 4 $48 659 14.70%

Tier 5 $68 605 17.01%

Total $684 730 10.20%

Powersport Portfolio Composition (in millions)

Tier 1

54%

Tier 2

19%

Tier 3

11%

Tier 4

Tier 5

10%

Historical Contribution Margin

Q2 2026 Loan Portfolio Disclosures

Contribution Margin (1) 2022 (EBG) 2023 (EBG) 2024 (EBG) 12/31/2025 3/31/2026 6/30/2026

Portfolio APR 7.42% 8.13% 9.02% 9.82% 10.14% 10.20%

Net Promo Accretion 0.69% 0.41% 0.74% 1.03% 1.30% 1.33%

Participation -0.84% -0.87% -0.87% -0.91% -1.08% -1.12%

Net Loss -0.62% -1.11% -1.39% -1.76% -2.06% -1.80%

Net Contribution Margin 6.65% 6.56% 7.52% 8.19% 8.30% 8.62%

(1) Historical contribution margin represents Evergreen Bank Group (EBG) performance through 6/30/2025. Contribution margin presented after 6/30/2025 excludes purchase

accounting adjustments.

Asset Type Outstanding % of Total Portfolio APR %

New $523 77% 9.54%

Used $161 23% 12.42%

Total $684 10.20%

Net Charge-offs (Recoveries) (in thousands)

Portfolio 9/30/2025 (Q) 12/31/2025 (Q) 3/31/2026 (Q) 6/30/2026 (Q) 6/30/2026 (TTM) NCO(R) %

Commercial (incl. Leases) $1,233 ($29) $1,495 $3,327 $6,026 0.42%

Commercial Real Estate Investor ($15) ($14) $3,928 $2,804 $6,703 0.58%

Commercial Real Estate Owner Occupied ($2) $1,125 ($14) ($1) $1,108 0.17%

Construction ($46) - - - ($46) (0.03%)

Residential Real Estate ($9) ($11) ($9) ($22) ($51) (0.02%)

Multifamily $181 - - - $181 0.05%

HELOC ($19) ($49) ($6) ($14) ($88) (0.04%)

Powersport $2,980 $4,466 $3,894 $2,826 $14,166 2.07%

Other $805 $493 $488 $328 $2,114 0.96%

Total $5,108 $5,981 $9,776 $9,248 $30,113 0.57%

6/30/2025 9/30/2025 12/31/2025 3/31/2026 6/30/2026

Beginning ACL Balance $41,551 $42,990 $75,037 $72,301 $72,126

Day 1 Credit Mark (PCD) - $17,540 - - -

Day 2 Credit Mark (Non-PCD) - $13,153 - - -

Plus: Provision $2,224 $6,462 $3,245 $9,602 $7,502

Less: Net Charge-off (Recovery) $785 $5,108 $5,981 $9,776 $9,248

Ending ACL Balance $42,990 $75,037 $72,301 $72,126 $70,380

Allowance for Credit Losses Quarterly Rollforward(2) (in thousands)

Q2 2026 Loan Portfolio Disclosures

(2) The Allowance for Credit Losses presented excludes the Allowance for Unfunded Commitments, which totaled $2.0 million as of June 30, 2026 and is reported within other

liabilities on the Statements of Condition.

GRAPHIC

Filename: osbc-20260722x8k001.jpg · Sequence: 4

Binary file (12346 bytes)

Download osbc-20260722x8k001.jpg

GRAPHIC

Filename: osbc-20260722xex99d1001.jpg · Sequence: 5

Binary file (10649 bytes)

Download osbc-20260722xex99d1001.jpg

GRAPHIC

Filename: osbc-20260722xex99d2g001.jpg · Sequence: 6

Binary file (29758 bytes)

Download osbc-20260722xex99d2g001.jpg

GRAPHIC

Filename: osbc-20260722xex99d2g002.jpg · Sequence: 7

Binary file (108937 bytes)

Download osbc-20260722xex99d2g002.jpg

GRAPHIC

Filename: osbc-20260722xex99d2g003.jpg · Sequence: 8

Binary file (96650 bytes)

Download osbc-20260722xex99d2g003.jpg

GRAPHIC

Filename: osbc-20260722xex99d2g004.jpg · Sequence: 9

Binary file (93157 bytes)

Download osbc-20260722xex99d2g004.jpg

GRAPHIC

Filename: osbc-20260722xex99d2g005.jpg · Sequence: 10

Binary file (92254 bytes)

Download osbc-20260722xex99d2g005.jpg

GRAPHIC

Filename: osbc-20260722xex99d2g006.jpg · Sequence: 11

Binary file (94927 bytes)

Download osbc-20260722xex99d2g006.jpg

GRAPHIC

Filename: osbc-20260722xex99d2g007.jpg · Sequence: 12

Binary file (96787 bytes)

Download osbc-20260722xex99d2g007.jpg

GRAPHIC

Filename: osbc-20260722xex99d2g008.jpg · Sequence: 13

Binary file (112052 bytes)

Download osbc-20260722xex99d2g008.jpg

GRAPHIC

Filename: osbc-20260722xex99d2g009.jpg · Sequence: 14

Binary file (98310 bytes)

Download osbc-20260722xex99d2g009.jpg

GRAPHIC

Filename: osbc-20260722xex99d2g010.jpg · Sequence: 15

Binary file (114848 bytes)

Download osbc-20260722xex99d2g010.jpg

XML — IDEA: XBRL DOCUMENT

XML

Filename: R1.htm · Sequence: 20

v3.26.1

Document and Entity Information

Jul. 22, 2026

Document and Entity Information [Abstract]

Document Type

8-K

Document Period End Date

Jul. 22, 2026

Entity Registrant Name

OLD SECOND BANCORP INC

Entity Incorporation, State or Country Code

Securities Act File Number

000-10537

Entity Tax Identification Number

36-3143493

Entity Address, Address Line One

37 South River Street

Entity Address, City or Town

Aurora

Entity Address, State or Province

Entity Address, Postal Zip Code

60507

City Area Code

630

Local Phone Number

892-0202

Written Communications

false

Soliciting Material

false

Pre-commencement Tender Offer

false

Pre-commencement Issuer Tender Offer

false

Title of 12(b) Security

Common Stock

Trading Symbol

OSBC

Security Exchange Name

NASDAQ

Entity Emerging Growth Company

false

Entity Central Index Key

0000357173

Amendment Flag

false

- Definition

Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.

+ References

No definition available.

+ Details

Name:

dei_AmendmentFlag

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Area code of city

+ References

No definition available.

+ Details

Name:

dei_CityAreaCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

+ References

No definition available.

+ Details

Name:

dei_DocumentPeriodEndDate

Namespace Prefix:

dei_

Data Type:

xbrli:dateItemType

Balance Type:

Period Type:

duration

- Definition

The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

+ References

No definition available.

+ Details

Name:

dei_DocumentType

Namespace Prefix:

dei_

Data Type:

dei:submissionTypeItemType

Balance Type:

Period Type:

duration

- Definition

Address Line 1 such as Attn, Building Name, Street Name

+ References

No definition available.

+ Details

Name:

dei_EntityAddressAddressLine1

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Name of the City or Town

+ References

No definition available.

+ Details

Name:

dei_EntityAddressCityOrTown

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Code for the postal or zip code

+ References

No definition available.

+ Details

Name:

dei_EntityAddressPostalZipCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Name of the state or province.

+ References

No definition available.

+ Details

Name:

dei_EntityAddressStateOrProvince

Namespace Prefix:

dei_

Data Type:

dei:stateOrProvinceItemType

Balance Type:

Period Type:

duration

- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityCentralIndexKey

Namespace Prefix:

dei_

Data Type:

dei:centralIndexKeyItemType

Balance Type:

Period Type:

duration

- Definition

Indicate if registrant meets the emerging growth company criteria.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityEmergingGrowthCompany

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

+ References

No definition available.

+ Details

Name:

dei_EntityFileNumber

Namespace Prefix:

dei_

Data Type:

dei:fileNumberItemType

Balance Type:

Period Type:

duration

- Definition

Two-character EDGAR code representing the state or country of incorporation.

+ References

No definition available.

+ Details

Name:

dei_EntityIncorporationStateCountryCode

Namespace Prefix:

dei_

Data Type:

dei:edgarStateCountryItemType

Balance Type:

Period Type:

duration

- Definition

The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityRegistrantName

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityTaxIdentificationNumber

Namespace Prefix:

dei_

Data Type:

dei:employerIdItemType

Balance Type:

Period Type:

duration

- Definition

Local phone number for entity.

+ References

No definition available.

+ Details

Name:

dei_LocalPhoneNumber

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 13e

-Subsection 4c

+ Details

Name:

dei_PreCommencementIssuerTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14d

-Subsection 2b

+ Details

Name:

dei_PreCommencementTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Title of a 12(b) registered security.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b

+ Details

Name:

dei_Security12bTitle

Namespace Prefix:

dei_

Data Type:

dei:securityTitleItemType

Balance Type:

Period Type:

duration

- Definition

Name of the Exchange on which a security is registered.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection d1-1

+ Details

Name:

dei_SecurityExchangeName

Namespace Prefix:

dei_

Data Type:

dei:edgarExchangeCodeItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14a

-Subsection 12

+ Details

Name:

dei_SolicitingMaterial

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Trading symbol of an instrument as listed on an exchange.

+ References

No definition available.

+ Details

Name:

dei_TradingSymbol

Namespace Prefix:

dei_

Data Type:

dei:tradingSymbolItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Securities Act

-Number 230

-Section 425

+ Details

Name:

dei_WrittenCommunications

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- References

No definition available.

+ Details

Name:

osbc_DocumentAndEntityInformationAbstract

Namespace Prefix:

osbc_

Data Type:

xbrli:stringItemType

Balance Type:

Period Type:

duration