a03_31x2026obkinvestorpr

1Q TWENTY26 INVESTOR PRESENTATION ORIGIN BANCORP, INC.

2 FORWARD-LOOKING STATEMENTS AND NON-GAAP MEASURES This presentation contains certain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include information regarding Origin Bancorp, Inc’s (“Origin”, “we”, “our” or the “Company”) future financial performance, business and growth strategies, projected plans and objectives, and any expected purchases of its outstanding common stock, and related transactions and other projections based on macroeconomic and industry trends, including changes to interest rates by the Federal Reserve and the resulting impact on Origin’s results of operations, estimated forbearance amounts and expectations regarding the Company’s liquidity, including in connection with advances obtained from the FHLB, which are all subject to change and may be inherently unreliable due to the multiple factors that impact broader economic and industry trends, and any such changes may be material. Such forward-looking statements are based on various facts and derived utilizing important assumptions and current expectations, estimates and projections about Origin and its subsidiaries, any of which may change over time and some of which may be beyond Origin’s control. Statements or statistics preceded by, followed by or that otherwise include the words “assumes,” “anticipates,” “believes,” “estimates,” “expects,” “foresees,” “intends,” “plans,” “projects,” and similar expressions or future or conditional verbs such as “could,” “may,” “might,” “should,” “will,” and “would” and variations of such terms are generally forward-looking in nature and not historical facts, although not all forward-looking statements include the foregoing words. Further, certain factors that could affect Origin’s future results and cause actual results to differ materially from those expressed in the forward- looking statements include, but are not limited to: (1) the impact of current and future economic conditions generally and in the financial services industry, nationally and within Origin’s primary market areas, including the impact of tariffs, as well as the financial stress on borrowers and changes to customer and client behavior as a result of the foregoing; (2) changes in benchmark interest rates and the resulting impacts on net interest income; (3) deterioration of Origin’s asset quality; (4) factors that can impact the performance of Origin’s loan portfolio, including real estate values and liquidity in Origin’s primary market areas; (5) the financial health of Origin’s commercial borrowers and the success of construction projects that Origin finances; (6) changes in the value of collateral securing Origin’s loans; (7) the impact of generative artificial intelligence; (8) Origin’s ability to anticipate interest rate changes and manage interest rate risk; (9) the impact of heightened regulatory requirements, reduced debit interchange and overdraft income and the possibility of facing related adverse business consequences if our total assets grow in excess of $10 billion as of December 31 of any calendar year; (10) the effectiveness of Origin’s risk management framework and quantitative models; (11) Origin’s inability to receive dividends from Origin Bank and to service debt, pay dividends to Origin’s common stockholders, repurchase Origin’s shares of common stock and satisfy obligations as they become due; (12) the impact of labor pressures; (13) changes in Origin’s operation or expansion strategy or Origin’s ability to prudently manage its growth and execute its strategy; (14) changes in management personnel; (15) Origin’s ability to maintain important customer relationships, reputation or otherwise avoid liquidity risks; (16) increasing costs as Origin grows deposits; (17) operational risks associated with Origin’s business; (18) significant turbulence or a disruption in the capital or financial markets and the effect of market disruption and interest rate volatility on our investment securities; (19) increased competition in the financial services industry, particularly from regional and national institutions, as well as from fintech companies; (20) compliance with governmental and regulatory requirements and changes in laws, rules, regulations, interpretations or policies relating to financial institutions; (21) periodic changes to the extensive body of accounting rules and best practices; (22) further government intervention in the U.S. financial system; (23) a deterioration of the credit rating for U.S. long-term sovereign debt; (24) Origin’s ability to comply with applicable capital and liquidity requirements, including its ability to generate liquidity internally or raise capital on favorable terms, including continued access to the debt and equity capital markets; (25) natural disasters and other adverse weather events, pandemics, acts of terrorism, war, and other matters beyond Origin’s control; (26) developments in our mortgage banking business, including loan modifications, general demand, and the effects of judicial or regulatory requirements or guidance; (27) fraud or misconduct by internal or external actors (including Origin employees); (28) cybersecurity threats or security breaches and the cost of defending against them; (29) Origin’s ability to maintain adequate internal controls over financial and non-financial reporting; and (30) potential claims, damages, penalties, fines, costs and reputational damage resulting from pending or future litigation, regulatory proceedings and enforcement actions. For a discussion of these and other risks that may cause actual results to differ from expectations, please refer to the sections titled “Cautionary Note Regarding Forward-Looking Statements” and “Risk Factors” in Origin’s most recent and future Annual Reports on Form 10-K filed with the Securities and Exchange Commission and any updates to those sections set forth in Origin’s subsequent Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. If one or more events related to these or other risks or uncertainties materialize, or if Origin’s underlying assumptions prove to be incorrect, actual results may differ materially from what Origin anticipates. Accordingly, you should not place undue reliance on any forward-looking statements. Any forward-looking statement speaks only as of the date on which it is made, and Origin does not undertake any obligation to publicly update or review any forward-looking statement, whether as a result of new information, future developments or otherwise. New risks and uncertainties arise from time to time, and it is not possible for Origin to predict those events or how they may affect Origin. In addition, Origin cannot assess the impact of each factor on Origin’s business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements. All forward-looking statements, expressed or implied, included in this communication are expressly qualified in their entirety by this cautionary statement. This cautionary statement should also be considered in connection with any subsequent written or oral forward-looking statements that Origin or persons acting on Origin’s behalf may issue. Annualized, pro forma, adjusted, projected, and estimated numbers are used for illustrative purposes only, are not forecasts, and may not reflect actual results. This presentation contains projected financial information with respect to Origin, including with respect to certain goals and strategic initiatives of Origin and the anticipated benefits thereof. This projected financial information constitutes forward-looking information and is for illustrative purposes only and should not be relied upon as necessarily being indicative of future results. The assumptions and estimates underlying such projected financial information are inherently uncertain and are subject to significant business, economic (including interest rate), competitive, and other risks and uncertainties. Actual results may differ materially from the results contemplated by the projected financial information contained herein and the inclusion of such projected financial information in this presentation should not be regarded as a representation by any person that such actions will be taken or accomplished or that the results reflected in such projected financial information with respect thereto will be achieved. Origin reports its results in accordance with generally accepted accounting principles in the United States ("GAAP"). However, management believes that certain supplemental non-GAAP financial measures may provide meaningful information to investors that is useful in understanding Origin's results of operations and underlying trends in its business. However, non-GAAP financial measures are supplemental and should be viewed in addition to, and not as an alternative for, Origin's reported results prepared in accordance with GAAP. The following are the non-GAAP measures used in this presentation: Pre-tax, pre-provision (“PTPP”) earnings, PTPP ROAA, return on average tangible common equity (“ROATCE”), tangible book value per common share, and tangible common equity to tangible assets. Please see “Reconciliation of Non-GAAP Financial Measures” at the end of this presentation for reconciliations of non-GAAP measures to the most directly comparable financial measures calculated in accordance with GAAP. ORIGIN BANCORP, INC. _______

ORIGIN BANCORP, INC. _______ LOUISIANA Entry: 1912 Loans: $1,474 Deposits: $3,365 DOLLARS IN MILLIONS, UNAUDITED (1) (2) 3 DEPOSITS & LOANS BY STATE Note: All financial information is as of March 31, 2026. Map location counts include full service branches only as of filing date. Please see slide 30 for all footnote references included above. MISSISSIPPI Entry: 2010 Loans: $567 Deposits: $614 8% 9% 39% 20% 53% 71% Loans (2)Deposits (1) ICS ICS TEXAS Dallas/Fort Worth Houston East Texas Entry: 2008 Entry: 2013 Entry: 2022 Loans: $2,476 Loans: $2,326 Loans: $394 Deposits: $2,036 Deposits: $1,562 Deposits: $935 Total Texas Loans: $5,196 Total Texas Deposits: $4,533 SOUTHEAST (AL/FL) Entry: 2024 Loans: $105 Deposits: $91 11 11 9 17 6 12 BEST BANKS TO WORK FOR IN AMERICA 13 CONSECUTIVE YEARS

4 T O D E L I V E R E L I T E L E V E L F I N A N C I A L P E R F O R M A N C E PRODUCTIVITY, DELIVERY & EFFICIENCY BALANCE SHEET OPTIMIZATION CULTURE & EMPLOYEE ENGAGEMENT UPDATED FINANCIAL OUTLOOK 4 Q 2 6* 2 0 2 6* Loan Growth - ex Warehouse (Yr/Yr) Mid to High-Single Digits Mid to High-Single Digits Deposit Growth (Yr/Yr) Mid to High-Single Digits Mid to High-Single Digits NIM 3.75% +/- 5 BPS 3.75% +/- 5 BPS NII Growth (Yr/Yr) Mid to High-Single Digits Mid to High-Single Digits Noninterest Income Growth (Yr/Yr)(3) Low to Mid-Single Digits Mid to High-Single Digits Noninterest Expense Growth (Yr/Yr)(3) Mid-Single Digits Mid-Single Digits PTPP ROAA > 1.72% > 1.65% Tax rate ~ 21.5% ~ 21.5% *Assumes two 25-bp cuts in 2026. NEAR TERM GOAL 1.15% + ROAA RUN RATE BY 4Q26 ULTIMATE TARGET TOP QUARTILE ROAA O P T I M I Z E O R I G I N Please see slide 30 for all footnote references included above.

STRONG NET MIGRATION INTO OUR MARKETS WEST -1,140,456 MIDWEST -512,765 NORTHEAST -1,504,304 SOUTH +3,157,525 5 TEXAS SOUTH ALABAMA & FLORIDA PANHANDLE l Baldwin County - 11th fastest growing metro area in the country l High-tech employment population ö 7 of top 10 US defense contractors have a presence in the region l Mobile, AL - 12th largest US port by tonnage l As of October 2025, Mobile Harbor is the deepest harbor on the Gulf Coast l 8th largest economy in the world l #1 in jobs created from December 2024 to December 2025 with 132,500 nonfarm jobs added l Home to 54 Fortune 500 company headquarters l Texas boasts the 2nd largest civilian workforce in the US with over 15 million workers l Texas is the leading destination for corporate relocation & expansion projects l Texas is home to 3.5 million small businesses and hundreds of publicly traded companies l As of 1Q26, Texas continues to lead the nation in high tech exports for the 13th year in a row ORIGIN STRATEGICALLY INVESTS I N T E X A S & S O U T H E A S T THE MOST DYNAMIC GROWTH MARKETS IN THE COUNTRY (4) Please see slide 30 for all footnote references included above. Net Domestic Migration from April 1, 2020 to July 1, 2025

6 ORIGIN BANCORP, INC. _______

ORIGIN BANCORP, INC. _______ • Net interest income was $87.2 million for 1Q26, reflecting an increase of $550,000, or 0.6%, compared to 4Q25, its highest level ever recorded. • NIM-FTE declined two basis points to 3.71% for 1Q26, compared to 4Q25, and the net interest spread of 2.89% is at its highest level since 4Q22. • Annualized ROAA was 1.11% for 1Q26, reflecting a decrease of eight basis points, or 6.7%, compared to 4Q25. • Total LHFI were $7.86 billion at 1Q26, reflecting an increase of $193.3 million, or 2.5%, compared to 4Q25. LHFI, excluding mortgage warehouse lines of credit (“mortgage warehouse LOC”), were $7.34 billion at 1Q26, reflecting an increase of $199.8 million, or 2.8%, compared to 4Q25. • Total deposits were $8.76 billion at 1Q26, reflecting an increase of $449.0 million, or 5.4%, compared to 4Q25. • During 1Q26, we repurchased 165,500 shares of our common stock at an average price of $41.27 per share. • During April 2026, our board approved an increase in our quarterly dividend from $0.15 to $0.25 per share. • Book value per common share was $40.81 at 1Q26, reflecting an increase of $0.53, or 1.3%, compared to 4Q25. Tangible book value per common share(5) was $35.61 at 1Q26, reflecting an increase of $0.57, or 1.6%, compared to 4Q25. Key Performance Metrics 1Q26 4Q25 B al an ce Sh ee t Total Loans Held for Investment ("LHFI") $ 7,864,221 $ 7,670,917 Total Assets 10,188,144 9,724,722 Total Deposits 8,756,268 8,307,247 In co m e St at em en t Net Income $ 27,693 $ 29,516 Pre-Tax, Pre-Provision ("PTPP") Earnings(5) 40,242 40,607 Diluted Earnings Per Share (“EPS”) 0.89 0.95 Se le ct ed R at io s Fully Tax-Equivalent Net Interest Margin (“NIM- FTE”) 3.71 % 3.73 % Return on Average Assets (annualized) ("ROAA") 1.11 1.19 PTPP ROAA (annualized)(5) 1.61 1.64 Return on Average Stockholders’ Equity (annualized) ("ROAE") 8.86 9.50 Return on Average Tangible Common Equity (annualized) ("ROATCE")(5) 10.15 10.95 Book Value per Common Share $ 40.81 $ 40.28 Tangible Book Value per Common Share(5) 35.61 35.04 Common Equity to Total Assets 12.37 % 12.82 % Tangible Common Equity to Tangible Assets(5) 10.97 11.34 Efficiency Ratio 61.32 60.74 Allowance for Loan Credit Losses ("ALCL") to Total Loans Held for Investment 1.26 1.26 DOLLARS IN THOUSANDS, EXCEPT PER SHARE AMOUNTS UNAUDITED 7 PERFORMANCE HIGHLIGHTS AT-A-GLANCE - FIRST QUARTER 2026 1Q26 Key Highlights Please see slide 30 for all footnote references included above.

ORIGIN BANCORP, INC. _______ TRENDING KEY MEASURES UNAUDITED Diluted EPS ($)Net Income ($) Total Deposits ($) 2Q 22 3Q 22 4Q 22 1Q 23 2Q 23 3Q 23 4Q 23 1Q 24 2Q 24 3Q 24 4Q 24 1Q 25 2Q 25 3Q 25 4Q 25 1Q 26 2Q 22 3Q 22 4Q 22 1Q 23 2Q 23 3Q 23 4Q 23 1Q 24 2Q 24 3Q 24 4Q 24 1Q 25 2Q 25 3Q 25 4Q 25 1Q 26 2Q 22 3Q 22 4Q 22 1Q 23 2Q 23 3Q 23 4Q 23 1Q 24 2Q 24 3Q 24 4Q 24 1Q 25 2Q 25 3Q 25 4Q 25 1Q 26 7,342 2Q 22 3Q 22 4Q 22 1Q 23 2Q 23 3Q 23 4Q 23 1Q 24 2Q 24 3Q 24 4Q 24 1Q 25 2Q 25 3Q 25 4Q 25 1Q 26 DOLLARS IN THOUSANDS 8 Total Loans Held for Investment ($) DOLLARS IN MILLIONS 2Q 22 3Q 22 4Q 22 1Q 23 2Q 23 3Q 23 4Q 23 1Q 24 2Q 24 3Q 24 4Q 24 1Q 25 2Q 25 3Q 25 4Q 25 1Q 26 DOLLARS IN MILLIONS DOLLARS IN MILLIONS Please see slide 30 for all footnote references included above. CAGR 9.9% CAGR 10.8% CAGR 9.2% 6,30321,311 27,693 Efficiency Ratio (%) 59.89 61.32 2Q 22 3Q 22 4Q 22 1Q 23 2Q 23 3Q 23 4Q 23 1Q 24 2Q 24 3Q 24 4Q 24 1Q 25 2Q 25 3Q 25 4Q 25 1Q 26 25.05 35.61 2Q 22 3Q 22 4Q 22 1Q 23 2Q 23 3Q 23 4Q 23 1Q 24 2Q 24 3Q 24 4Q 24 1Q 25 2Q 25 3Q 25 4Q 25 1Q 26 Tangible Book Value per Common Share(5) ($) (Non-GAAP) 2Q 22 3Q 22 4Q 22 1Q 23 2Q 23 3Q 23 4Q 23 1Q 24 2Q 24 3Q 24 4Q 24 1Q 25 2Q 25 3Q 25 4Q 25 1Q 26 Return on Average Assets (%) CAGR 9.8% 0.89 7,864 3.71 2Q 22 3Q 22 4Q 22 1Q 23 2Q 23 3Q 23 4Q 23 1Q 24 2Q 24 3Q 24 4Q 24 1Q 25 2Q 25 3Q 25 4Q 25 1Q 26 NIM - FTE (%) 3.23 1.11 1.08 4,995 5,528 8,756 0.90 Loans Held for Investment excl. Mortgage Warehouse LOC ($)

ORIGIN BANCORP, INC. _______ 148 10,188 1997 2002 2007 2012 2017 2022 1Q26 DELIVERING STOCKHOLDER VALUE DOLLARS IN MILLIONS Total Assets ($) Core Deposits(6) ($) 3,011 8,351 2017 2018 2019 2020 2021 2022 2023 2024 2025 1Q26 CAGR 16.2% CAGR 13.2% 9 1,931 2,338 Origin Bancorp, Inc. Cumulative Return ($) KBW Nasdaq Bank Total Return Index ($) 12 /3 1/ 96 12 /3 1/ 01 12 /3 1/ 06 12 /3 1/ 11 12 /3 1/ 16 12 /3 1/ 21 0 500 1,000 1,500 2,000 2,500 Total Stockholder Return(7) ($) IPO May 2018 Please see slide 30 for all footnote references included above. DOLLARS IN MILLIONS UNAUDITED Tangible Book Value per Common Share(5) ($) 18.74 35.61 2017 2018 2019 2020 2021 2022 2023 2024 2025 1Q26 CAGR 8.1% 12 /3 1/ 25 148 9,725 10,188 1997 2001 2005 2009 2013 2017 2021 2025 1Q26 DOLLARS IN MILLIONS Total Assets ($) CAGR 16.2% 148 10,188 1997 2001 2005 2009 2013 2017 2021 2025 DOLLARS IN MILLIONS Total Assets ($) CAGR 16.2%

ORIGIN BANCORP, INC. _______ 10 1,152 1,218 1,311 1,741 1,956 2,247 2,620 4,747 5,276 5,250 5,035 5,196 DFW Houston East Texas 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 1Q26 Deposit Trends by Texas Market(10)(11) ($) Loan Trends by Texas Market(2)(9) ($) TEXAS GROWTH STORY Texas Franchise Highlights DOLLARS IN MILLIONS • 31 locations throughout 11 counties including the 4th and 5th largest MSAs in the United States.(8) • Texas franchise represents 71% of LHFI(2) and 53% of deposits(1) at March 31, 2026. 1,128 1,114 1,171 1,395 1,854 2,574 3,132 4,261 4,172 4,524 4,313 4,533 DFW Houston East Texas 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 1Q26 Please see slide 30 for all footnote references included above. DOLLARS IN MILLIONS UNAUDITED CAGR 14.5% CAGR 15.8%

ORIGIN BANCORP, INC. _______ 193 184 30 (6) 134 69 (5) 56 1Q26 vs 4Q25 4Q25 vs 3Q25 Total Loans Held for Investment Commercial and Industrial Construction/Land/Land Development Mortgage Warehouse Lines of Credits LOAN GROWTH 6,805 7,331 7,225 7,142 7,342 5,593 7,142 7,342 1,212 Origin Acquired 2022 2023 2024 2025 1Q26 0 2,000 4,000 6,000 DOLLARS IN MILLIONS IDT Loans Held for Investment Growth excluding Mortgage Warehouse Lines of Credit ($) 2,894 3,013 2,979 2,994 3,173 2,267 2,994 3,173 627 Origin Acquired 2022 2023 2024 2025 1Q26 0 1,000 2,000 3,000 Commercial and Industrial and Owner-Occupied Commercial Real Estate Growth ($) Please see slide 30 for all footnote references included above. DOLLARS IN MILLIONS UNAUDITED Loans Held for Investment Change ($) 11 DOLLARS IN MILLIONS

ORIGIN BANCORP, INC. _______ Commercial & Industrial (“C&I”) 27% Owner-Occupied Commercial Real Estate (“CRE”) Mortgage Warehouse Lines of Credit Non-Owner- Occupied CRE 19% Construction/Land/Land Development (“C&D”) Multifamily Residential Real Estate Single-Family Residential Real Estate & Consumer Real Estate & Construction: 8% Multifamily Residential Real Estate: 7% Retail Shopping: 6% Office Building: 5% Healthcare: 2% Hotels: 1% Restaurants: 1% Auto-Related: 1% Multifamily under Construction: 1% Misc. : 2% Finance & Insurance: 8% Real Estate & Construction: 7% Mortgage Warehouse LOC: 7% Transportation Services: 3% Energy: 3% Retail Shopping: 2% Banks : 2% Healthcare: 2% Restaurants: 1% Professional Services: 1% Consumer Services: 1% Retail Dealers: 1% Entertainment & Recreation: 1% Commercial Services: 1% Misc. : 7% 12 WELL DIVERSIFIED LOAN PORTFOLIO (Dollars in thousands) 1Q26 4Q25 3Q25 2Q25 1Q25 Commercial and Industrial 2,173,126 1,989,218 1,919,782 2,011,178 2,022,085 Owner-Occupied Commercial Real Estate 999,440 1,004,801 986,859 972,788 937,985 Mortgage Warehouse Lines of Credit 522,290 528,781 472,968 574,748 404,131 Total Commercial 3,694,856 3,522,800 3,379,609 3,558,714 3,364,201 Non-Owner-Occupied Commercial Real Estate 1,511,138 1,519,104 1,520,020 1,455,771 1,445,864 Construction/Land/Land Development 641,273 611,220 615,778 653,748 798,609 Multifamily Residential Real Estate 555,527 553,149 540,601 529,899 489,765 Single-Family Residential Real Estate 1,442,792 1,444,611 1,460,696 1,465,535 1,465,192 Consumer Loans 18,635 20,033 20,395 20,779 21,895 Total Loans Held for Investment (“LHFI”) 7,864,221 7,670,917 7,537,099 7,684,446 7,585,526 Loan Portfolio Details ($) C&I, Owner-Occupied CRE & Mtg. Warehouse LOC: $3,695 million C&I, Owner-Occupied CRE, Mortgage Warehouse LOC: 47% Non-Owner-Occupied CRE, C&D, Multi-Family: 34% Loan Composition at March 31, 2026: $7,864 million Please see slide 30 for all footnote references included above. UNAUDITED (12) Non-Owner-Occupied CRE, C&D and Multi-Family: $2,708 million 13% 7% 19% 7% 8%

ORIGIN BANCORP, INC. _______ 1.71 1.69 1.84 1.93 1.97 0.15 0.12 1.65 0.17 0.15 Classified Assets / Loans & OREO Net Charge-Offs / Average LHFI (annualized) 1Q25 2Q25 3Q25 4Q25 1Q26 1.10 1.14 1.18 1.07 1.12 0.56 0.16 0.10 0.19 0.22 Nonperforming Assets / Loans & OREO Past due 30 to 89 days and still accruing / LHFI 1Q25 2Q25 3Q25 4Q25 1Q26 13 CREDIT QUALITY Asset Quality Trends (%) Allowance for Loan Credit Losses 92,011 92,426 96,259 96,782 99,015 1.21 1.20 1.28 1.26 1.26 1.28 1.29 1.35 1.34 1.34 ALCL as a percentage of LHFI, adjusted (%) ALCL as a percentage of LHFI (%) ALCL ($) 1Q25 2Q25 3Q25 4Q25 1Q26 DOLLARS IN THOUSANDS (13) Please see slide 30 for all footnote references included above. UNAUDITED 18,981 (123) (3,858) (8,605) 4Q25 Downgrades OREO net transactions Charge-offs Payments 1Q26 83,358 87,306 88,859 81,878 88,273 Total NPA ($) 1Q25 2Q25 3Q25 4Q25 1Q26 Nonperforming Asset Trends ($) • Provision expense for loan credit loss for 1Q26 was $5.0 million, compared to $3.7 million in 4Q25. • Net charge-offs for the quarter were $2.8 million, down from $3.2 million for 4Q25, and represent an annualized charge-off rate of 0.15%.

ORIGIN BANCORP, INC. _______ 14 SELECTED SECTORS - KEY PORTFOLIO METRICS March 31, 2026 Non-Owner-Occupied Commercial Real Estate Office Multifamily Residential Real Estate + Under Construction Hotel Retail Shopping Outstanding Loan Balance $ 380,027 $ 639,365 $ 103,198 $ 651,993 % of Loans Held for Investment 4.83 % 8.13 % 1.31 % 8.29 % Avg. Loan Size $ 2,405 $ 3,761 $ 4,691 $ 1,626 Weighted Avg. Loan- to-Value 55.30 % 57.83 % 50.11 % 63.01 % Past Due 30 to 89 Days and Still Accruing Loans/Loans — 0.18 0.09 0.05 Classified Loans / Loans 1.10 0.58 — 0.79 Nonperforming Loans / Loans 1.10 — — — Net Charge-offs / Avg. Loans 0.21 — — — Allowance for Loan Credit Losses / Loans 0.70 1.27 0.91 0.66 DOLLARS IN THOUSANDS, UNAUDITED

ORIGIN BANCORP, INC. _______ MBS: 41% CMO: 29% Municipal: 25% Corporate: 5% 1,163 1,156 1,128 1,201 1,201 3.15 3.16 3.62 3.46 3.46 Total Securities ($) Yield (%) 1Q25 2Q25 3Q25 4Q25 1Q26 Investment Securities Average Balance and Yield INVESTMENT SECURITIES DOLLARS IN MILLIONS • Total securities portfolio weighted average effective duration was 4.14 years at March 31, 2026, compared to 4.15 years at December 31, 2025. • Expected principal cash flows from investments with no rate changes: • 2026: $118.2 million • 2027: $131.9 million • 2028: $125.0 million 15 (90.4) (73.6) (61.2) (54.1) (60.8) 1Q25 2Q25 3Q25 4Q25 1Q26 Accumulated Other Comprehensive Loss(14) ($) Investment Securities - AFS at March 31, 2026 Please see slide 30 for all footnote references included above. $1.15B DOLLARS IN MILLIONS UNAUDITED

ORIGIN BANCORP, INC. _______ Total Loans at March 31, 2026 (Dollars in thousands) Repricing or Maturity Term Rate Structure 1 Year or less > 1 to 3 Years > 3 to 5 Years > 5 to 10 Years > 10 Years Total Floating Rate(15) Variable Rate(15) Fixed Rate Commercial and Industrial $ 1,762,484 $ 231,174 $ 118,937 $ 60,531 $ — $ 2,173,126 $ 1,710,117 $ 1,128 $ 461,881 Owner-Occupied Commercial Real Estate 468,067 242,646 166,136 122,591 — 999,440 320,550 3,287 675,603 Mortgage Warehouse Lines of Credit 522,290 — — — — 522,290 522,290 — — Total Commercial 2,752,841 473,820 285,073 183,122 — 3,694,856 2,552,957 4,415 1,137,484 Non-Owner-Occupied Commercial Real Estate 887,401 407,456 163,115 53,166 — 1,511,138 655,102 2,346 853,690 Construction/Land/Land Development 471,657 83,294 65,830 20,021 471 641,273 379,113 7,224 254,936 Multifamily Residential Real Estate 398,240 92,375 50,577 11,132 3,203 555,527 310,721 — 244,806 Single-Family Residential Real Estate 423,124 353,991 289,086 166,110 210,481 1,442,792 265,943 688,650 488,199 Consumer 9,687 6,047 2,433 373 95 18,635 4,284 24 14,327 Total Loans Held for Investment $ 4,942,950 $ 1,416,983 $ 856,114 $ 433,924 $ 214,250 $ 7,864,221 $ 4,168,120 $ 702,659 $ 2,993,442 % of Total 62 % 18 % 11 % 6 % 3 % 100 % 53 % 9 % 38 % Weighted Average Coupon Rate 6.07 5.49 6.09 4.55 5.61 5.87 6.31 4.85 5.51 AFS & HTM Securities at March 31, 2026 (Dollars in thousands) Maturity & Projected Principal Cashflow Total1 Year or less > 1 to 3 Years > 3 to 5 Years > 5 to 10 Years > 10 Years Projected Cash Flow $ 153,853 $ 250,969 $ 235,680 $ 437,080 $ 158,014 $ 1,235,596 % of Total 12 % 20 % 19 % 36 % 13 % 100 % LOANS & SECURITIES- REPRICING OR MATURITY 16 UNAUDITED Please see slide 30 for all footnote references included above.

ORIGIN BANCORP, INC. _______ Finance & Insurance: 10% Real Estate Rental & Leasing: 7% Other Business Deposits <2%: 7% Construction: 5% Professional, Scientific, & Technical Svcs: 5% Mgmt of Companies & Enterprises: 4% Affiliate: 4% Other Svcs (except Public Administration): 3% Manufacturing: 3% Health Care & Social Assistance:2% Mining: 2% Misc: 5% Consumer 30% Public Funds: 13% 29% 23%6% 37% 4% 1% 17 DEPOSIT DETAIL (Dollars in thousands) 1Q26 4Q25 3Q25 2Q25 1Q25 QoQ % Δ Total Deposits $ 8,756,268 $ 8,486,568 $ 8,510,842 $ 8,505,464 $ 8,251,125 3.2 % FDIC Insured (3,464,116) (3,464,116) (3,442,636) (3,447,538) (3,425,268) — FDIC Insured Reciprocal (1,093,952) (1,093,952) (799,221) (801,145) (801,699) — FDIC Insured Brokered Deposits (431,609) (431,609) (636,814) (597,110) (444,989) — Total Estimated FDIC Uninsured Deposits 3,766,591 3,496,891 3,632,171 3,659,671 3,579,169 7.7 Collateralized Public Funds (714,431) (714,431) (771,419) (836,150) (849,603) — Uninsured/ Uncollateralized Deposits ($) $ 3,052,160 $ 2,782,460 $ 2,860,752 $ 2,823,521 $ 2,729,566 9.7 Uninsured/ Uncollateralized Deposits (%) 34.9 % 32.8 % 33.6 % 33.2 % 33.1 % Deposit Detail Deposit Concentration(1) at March 31, 2026: $8,756 million Deposit Composition at March 31, 2026: $8,756 million MississippiLouisiana Texas- DFW TX- East TexasTexas- Houston Please see slide 30 for all footnote references included above. UNAUDITED Southeast 16% 17% 18% 38% 10% 1% (Dollars in thousands) 1Q26 4Q25 3Q25 2Q25 1Q25 QoQ % Δ Total Deposits $ 8,756,268 $ 8,307,247 $ 8,331,830 $ 8,123,036 $ 8,338,412 5.4 % FDIC Insured (3,490,869) (3,465,133) (3,407,017) (3,372,038) (3,546,288) 0.7 FDIC Insured Reciprocal (1,277,061) (915,033) (1,056,176) (992,673) (1,022,142) 39.6 FDIC Insured Brokered Deposits — — — (25,000) (50,000) — Total Estimated FDIC Uninsured Deposits 3,988,338 3,927,081 3,868,637 3,733,325 3,719,982 1.6 Collateralized Public Funds (840,360) (860,049) (690,933) (830,182) (822,009) (2.3) Uninsured/ Uncollateralized Deposits ($) $ 3,147,978 $ 3,067,032 $ 3,177,704 $ 2,903,143 $ 2,897,973 2.6 Uninsured/ Uncollateralized Deposits (%) 36.0 % 36.9 % 38.1 % 35.7 % 34.8 % Deposit Detail 19% 1% 14% 52% 13% 1% 449 237 154 83 7 (32) Total Deposits Money Market Interest-Bearing Demand Noninterest-Bearing Deposit Savings Time Deposits (Non- Brokered) Linked Quarter Deposit Change ($) DOLLARS IN MILLIONS, PERIOD END BALANCES Customer Deposits +(1)MM Commercial: 57% Commercial: 57% Consumer: 30% Public Funds: 13%

ORIGIN BANCORP, INC. _______ 3.69 3.45 3.37 3.30 3.08 3.23 3.20 3.20 2.90 2.66 2.52 2.47 2.46 2.20 2.05 Time Deposits Total Interest-Bearing Deposits Total Deposits 1Q25 2Q25 3Q25 4Q25 1Q26 18 8,348 8,159 8,232 8,372 8,647 5,539 5,409 5,511 5,557 5,857 1,837 1,881 1,901 2,002 1,978 972 869 820 813 812 Interest-Bearing Demand Noninterest-Bearing Time Deposits 1Q25 2Q25 3Q25 4Q25 1Q26 Average Deposits ($) DEPOSIT TRENDS IDT DOLLARS IN MILLIONS UNAUDITED Deposit Cost Trends (QTD Annualized) (%) Time Deposit Repricing Schedule(17) Maturity Balance ($) Weighted Average Rate (%) 2Q26 380 3.24 3Q26 229 2.93 4Q26 102 2.74 1Q27 52 2.30 2Q27+ 34 1.48 Total 797 2.95 DOLLARS IN MILLIONS 57.14 57.35 66.00 71.00 69.90 68.53 66.86 5.26 4.65 4.33 4.33 4.30 3.90 3.64 3.14 2.79 2.52 2.47 2.46 2.20 2.05 Cumulative Deposit Beta Average Quarterly Fed Funds Rate Cost of Total Deposit 3Q24 4Q24 1Q25 2Q25 3Q25 4Q25 1Q26 Please see slide 30 for all footnote references included above. Total Deposit Beta (%) Customer Deposits +(1)MM (16)

ORIGIN BANCORP, INC. _______ 2.58 2.52 2.49 2.26 2.06 3.23 3.20 3.20 2.90 2.66 2.52 2.47 2.46 2.20 2.05 Cost of Total Deposits & Borrowings Cost of Interest Bearing Deposits Cost of Total Deposits 1Q25 2Q25 3Q25 4Q25 1Q26 19 YIELDS AND COSTS Yield on Loans Held for Investment (%) Cost of Funds (%) • At 1Q26, Loans Held for Investment with fixed rates = 38% and Loans Held for Investment with floating/variable rates = 62%. • At 1Q26, SOFR-based = $2.84 billion, Prime-based = $1.84 billion. UNAUDITED 6.33 6.33 6.33 6.22 6.06 7.50 7.50 7.46 7.02 6.75 4.36 4.33 4.35 4.09 3.68 Yield on Loans Held for Investment Avg. Prime Rate 30 Day Avg. SOFR 1Q25 2Q25 3Q25 4Q25 1Q26

ORIGIN BANCORP, INC. _______ 78,459 82,136 83,704 86,694 87,244 64,368 64,802 66,021 68,493 70,5935,047 8,217 7,393 7,723 6,3899,044 9,117 10,290 10,478 10,262 3.44 3.61 3.65 3.73 3.71 Net Interest Income excl. Mtg Warehouse LOC & Invest. Secur. NII ($) Mtg. Warehouse LOC Interest Income ($) Investment Securities Net Interest Income ($) NIM (FTE) (%) 1Q25 2Q25 3Q25 4Q25 1Q26 20 DOLLARS IN THOUSANDS, UNAUDITED NET INTEREST INCOME AND NIM TRENDS 3.73 0.07 0.05 0.02 (0.01) (0.03) (0.03) (0.03) (0.06) 4Q25 Subordinated debentures Savin gs a nd IB Transc. Acct s Tim e Deposits IB Bal. D FB Other Commerci al a nd Industr ial MW LOC Real E sta te lo ans 1Q26 3.25 3.50 3.75 4.00 24.64 29.52 21.01 8.58 2.041.54 2.480.77 2.18 3.65 4.51 5.26 5.33 4.65 3.90 Cumulative NIM-FTE Beta Average Quarterly Fed Funds Rate 2Q23 3Q23 4Q23 1Q24 3Q24 4Q24 1Q25 2Q25 1Q26 NIM Beta - 1Q26 (%) 2.48 2.48 4.99 NIM-FTE Changes - 1Q26 (%) NIM-FTE Changes - 1Q26 (%) 73,32372,989 1,362 1,537 568 432 (298) (3,267) 4Q 23 RE Lo an s C&I MW LO C Othe r FH LB & O the r Bor ro wing s Sav ing s & IB Tr an sa c. Acc ts. 1Q 24 40,000 60,000 80,000 • Our net interest spread increased to 2.89%, or nine basis points, compared to 4Q25 and is at its highest level since the quarter ended December 31, 2022. • Net interest income increased $550,000 during 1Q26 compared to 4Q25 and $8.8 million compared to 1Q25. • Our NIM-FTE decreased two-basis points during 1Q26 compared to 4Q25 and increased 27-basis points compared to 1Q25. Net Interest Income & NIM 3.71 Yield/Rate 1Q26 4Q25 3Q25 2Q25 1Q25 YoY Change NIM - FTE 3.71 3.73 3.65 3.61 3.44 27 bps Loans Held For Investment 6.06 6.22 6.33 6.33 6.33 (27) bps Securities 3.46 3.46 3.62 3.16 3.15 31 bps Cost of Total Deposits 2.05 2.20 2.46 2.47 2.52 (47) bps Interest Earning Assets 5.56 5.76 5.89 5.87 5.79 (23) bps Interest Bearing Liabilities 2.67 2.96 3.22 3.25 3.30 (63) bps Yield/Rate Highlights (%) +27 bps

ORIGIN BANCORP, INC. _______ 94,746 98,110 100,783 103,730 103,601 Net Interest Income Noninterest Income 1Q25 2Q25 3Q25 4Q25 1Q26 15,859 15,766 14,551 13,782 17,406 7,927 6,661 6,598 5,931 9,597 4,716 4,927 4,965 5,043 4,951 2,301 2,809 2,262 2,128 2,295915 1,369 726 680 563 Insurance Commission & Fee Income Service Charges & Fees Other Fee Income Mortgage Banking Revenue 1Q25 2Q25 3Q25 4Q25 1Q26 21 Major Components of Noninterest Income ($) Net Interest Income + Noninterest Income ($)(3) NET REVENUE DISTRIBUTION Components of Other Noninterest Income ($) 1Q26 4Q25 3Q25 2Q25 1Q25 Argent Investment Income (18) 1,754 1,980 1,227 — — Limited Partnership Investment Loss (18) (3,271) (121) (677) (1,909) (1,692) Swap Fee Income 54 58 1,387 1,435 533 Change in fair value of equity investments — — 6,972 — — Loss on Sale of Securities — — — (14,448) — Other 852 1,037 2,668 524 902 Total Components of Other Noninterest Income (611) 2,954 11,577 (14,398) (257) Major Components of Noninterest Income 17,406 13,782 14,551 15,766 15,859 Total Noninterest Income 16,795 16,736 26,128 1,368 15,602 83.5% 84.2% Please see slide 30 for all footnote references included above. DOLLARS IN THOUSANDS, UNAUDITED 84.3%83.1%83.7%

ORIGIN BANCORP, INC. _______ 22 Efficiency Ratio (%) NONINTEREST EXPENSE ANALYSIS Major Components of Noninterest Expense ($) 64.81 66.82 68.86 83.85 65.99 74.23 56.48 61.32 Consolidated Efficiency Ratio 2Q24 3Q24 4Q24 1Q25 2Q25 3Q25 4Q25 1Q26 Operating Leverage (%) 2.59 2.49 2.61 2.57 2.56 2.53 2.54 2.56 66.82 68.86 83.85 65.99 74.23 56.48 60.74 61.32 Noninterest Expense / Average Assets Efficiency Ratio 2Q24 3Q24 4Q24 1Q25 2Q25 3Q25 4Q25 1Q26 53,965 54,004 53,235 52,390 53,853 37,731 38,280 37,863 37,015 38,397 8,544 7,187 7,079 6,961 6,984 2,957 3,432 3,526 3,672 4,050 2,972 3,337 3,184 3,243 2,937 1,761 1,768 1,583 1,499 1,485 Salaries and Employee Benefits Occupancy and Equipment, net Data Processing Office and Operations Intangible Asset Amortization 1Q25 2Q25 3Q25 4Q25 1Q26 Components of Other Noninterest Expense ($) 1Q26 4Q25 3Q25 2Q25 1Q25 Professional Services 2,649 2,703 1,395 1,285 1,250 Electronic Banking 1,442 1,545 1,470 1,359 1,354 Advertising and Marketing 1,360 1,746 1,524 1,158 1,133 Regulatory Assessments 1,335 1,528 1,269 1,345 1,392 Loan-Related Expenses 895 787 979 669 599 Other Expenses 2,263 2,124 2,156 2,163 2,375 Total Components of Other Noninterest Expense 9,944 10,433 8,793 7,979 8,103 Major Components of Noninterest Expense 53,853 52,390 53,235 54,004 53,965 Total Noninterest Expense 63,797 62,823 62,028 61,983 62,068 DOLLARS IN THOUSANDS, UNAUDITED

ORIGIN BANCORP, INC. _______ 86.1 87.5 84.8 86.0 83.8 LHFI excl. Mortgage Warehouse LOC to Total Deposits LHFI to Total Deposits 1Q25 2Q25 3Q25 4Q25 1Q26 1,079 1,099 1,265 814 1,094 486 334 627 424 666 593 765 638 390 428 Cash and Cash Equivalents Liquid Securities 1Q25 2Q25 3Q25 4Q25 1Q26 Cash and Cash Equivalents + Liquid Securities ($) 23 LIQUIDITY Loan to Deposit Ratios (%) UNAUDITED Liquidity Sources 1Q26 Borrowed Funds as a Percent of Total Liabilities (%) DOLLARS IN MILLIONS DOLLARS IN THOUSANDS PERIOD END BALANCES PERIOD END BALANCES 1.19 2.57 1.20 0.42 0.33 Borrowed Funds as a Percent of Total Liabilities 1Q25 2Q25 3Q25 4Q25 1Q26 FHLB Borrowing Availability $ 2,398,777 Unpledged AFS Securities 458,191 Fed Funds Lines and Fed Discount Window 1,478,471 Total Additional Liquidity Sources a $ 4,335,439 Cash and Cash Equivalent b $ 666,203 Uninsured, Non-collateralized Deposits c $ 3,147,978 Coverage Ratio d = (a+b)/c 1.59x 91.0 94.6 90.5 92.3 89.8

ORIGIN BANCORP, INC. _______ 24 CAPITAL Common Equity Tier 1 Capital to Risk-Weighted Assets(19) (%) ICap ICap Total Capital to Risk-Weighted Assets(19) (%) Tier 1 Capital to Risk-Weighted Assets(19) (%) Tier 1 Capital to Average Assets (Leverage Ratio)(19) (%) Please see slide 30 for all footnote references included above. UNAUDITED Stock Repurchase Program • 165,500 shares repurchased in 1Q26 at an average price per share of $41.27. • There was $31.7 million remaining repurchase authorization at March 31, 2026. 11.5 11.7 11.7 11.9 11.7 11.2 11.2 11.0 10.9 10.9 Company Level Origin Bank Level 1Q25 2Q25 3Q25 4Q25 1Q26 13.8 13.7 13.8 13.7 13.8 13.4 13.1 12.9 12.6 12.8 Company Level Origin Bank Level 1Q25 2Q25 3Q25 4Q25 1Q26 15.8 15.7 15.9 14.9 15.0 14.6 14.3 14.2 13.8 14.0 Company Level Origin Bank Level 1Q25 2Q25 3Q25 4Q25 1Q26 13.6 13.5 13.6 13.5 13.6 13.4 13.1 12.9 12.6 12.8 Company Level Origin Bank Level 1Q25 2Q25 3Q25 4Q25 1Q26 Well Capitalized 5.0% Well Capitalized 6.5% Well Capitalized 10.0% Well Capitalized 8.0% 75,121 9,185 14,327 79,855 11,501 4,753 4,769 4,782 4,745 4,669 4,382 9,510 1,914 6,832 70,368 73,196 0.15 0.15 0.15 0.15 0.15 Dividends Declared Common Shares Repurchased Sub-debt Redeemed Dividends per Share 1Q25 2Q25 3Q25 4Q25 1Q26 Uses of Regulatory Capital ($) DOLLARS IN THOUSANDS, EXCEPT PER SHARE AMOUNTS (20) (20) (20)

ORIGIN BANCORP, INC. _______ QTD 1Q26 4Q25 $ Impact EPS Impact (21) $ Impact EPS Impact (21) Notable interest expense items: OID amortization - subordinated debenture redemption $ — $ — $ (783) $ (0.02) Notable provision expense items: Provision expense on relationships related to or impacted by questioned banker activity — — (10) — Provision expense related to borrower fraud — — (13) — Notable noninterest income items: Insurance recovery income related to questioned banker activity 438 0.01 483 0.01 Notable noninterest expense items: Operating expense related to questioned banker activity (542) (0.01) (698) (0.02) Operating expense related to strategic Optimize Origin initiatives(22) — — (51) — Operating expense related to borrower fraud (473) (0.01) (587) (0.01) Total notable items $ (577) (0.01) $ (1,659) (0.04) 25 DOLLARS IN THOUSANDS, EXCEPT PER SHARE AMOUNTS, UNAUDITED NOTABLE ITEMS Please see slide 30 for all footnote references included above.

ORIGIN BANCORP, INC. _______ 1Q26 4Q25 Calculation of PTPP earnings: Net income $ 27,693 $ 29,516 Provision for credit losses 4,965 3,158 Income tax expense 7,584 7,933 PTPP earnings (non-GAAP) $ 40,242 $ 40,607 Calculation of PTPP ROAA: PTPP earnings $ 40,242 $ 40,607 Divided by number of days in the quarter 90 92 Multiplied by the number of days in the year 365 365 PTPP earnings, annualized $ 163,204 $ 161,104 Divided by total average assets $ 10,126,491 $ 9,829,752 ROAA (annualized) (GAAP) 1.11 % 1.19 % PTPP ROAA (annualized) (non-GAAP) 1.61 1.64 Calculation of tangible common equity to tangible assets: Total assets $ 10,188,144 $ 9,724,722 Goodwill (128,679) (128,679) Other intangible assets, net (31,877) (33,362) Tangible assets 10,027,588 9,562,681 Total common stockholders' equity $ 1,260,275 $ 1,246,685 Goodwill (128,679) (128,679) Other intangible assets, net (31,877) (33,362) Tangible common equity 1,099,719 1,084,644 Common equity to total assets 12.37 % 12.82 % Tangible common equity to tangible assets (non-GAAP) 10.97 11.34 26 DOLLARS IN THOUSANDS, UNAUDITED RECONCILIATION OF NON-GAAP FINANCIAL MEASURES

ORIGIN BANCORP, INC. _______ 1Q26 4Q25 Calculation of ROATCE: Net income $ 27,693 $ 29,516 Divided by number of days in the quarter 90 92 Multiplied by the number of days in the year 365 365 Annualized net income $ 112,311 $ 117,102 Total average stockholders' equity $ 1,267,888 $ 1,232,878 Average goodwill (128,679) (128,679) Average other intangible assets, net (32,679) (34,293) Average tangible common equity 1,106,530 1,069,906 ROAE (annualized) (GAAP) 8.86 % 9.50 % ROATCE (annualized) (non-GAAP) 10.15 10.95 27 DOLLARS IN THOUSANDS, UNAUDITED RECONCILIATION OF NON-GAAP FINANCIAL MEASURES

ORIGIN BANCORP, INC. _______ Calculation of tangible book value per common share: 1Q26 4Q25 3Q25 2Q25 1Q25 4Q24 3Q24 2Q24 Total common stockholders' equity $ 1,260,275 $ 1,246,685 $ 1,214,756 $ 1,205,769 $ 1,180,177 $ 1,145,245 $ 1,145,673 $ 1,095,894 Goodwill (128,679) (128,679) (128,679) (128,679) (128,679) (128,679) (128,679) (128,679) Other intangible assets, net (31,877) (33,362) (34,861) (36,444) (38,212) (37,473) (39,272) (41,177) Tangible common equity 1,099,719 1,084,644 1,051,216 1,040,646 1,013,286 979,093 977,722 926,038 Divided by common shares outstanding at period end 30,879,462 30,952,428 30,967,768 31,224,718 31,244,006 31,197,574 31,167,410 31,108,667 Book value per common share (GAAP) $ 40.81 $ 40.28 $ 39.23 $ 38.62 $ 37.77 $ 36.71 $ 36.76 $ 35.23 Tangible book value per common share (non-GAAP) 35.61 35.04 33.95 33.33 32.43 31.38 31.37 29.77 1Q24 4Q23 3Q23 2Q23 1Q23 4Q22 3Q22 2Q22 Total common stockholders' equity $ 1,078,853 $ 1,062,905 $ 998,945 $ 997,859 $ 992,587 $ 949,943 $ 907,024 $ 646,373 Goodwill (128,679) (128,679) (128,679) (128,679) (128,679) (128,679) (136,793) (34,153) Other intangible assets, net (43,314) (45,452) (42,460) (44,724) (47,277) (49,829) (52,384) (15,900) Tangible common equity 906,860 888,774 827,806 824,456 816,631 771,435 717,847 596,320 Divided by common shares outstanding at period end 31,011,304 30,986,109 30,906,716 30,866,205 30,780,853 30,746,600 30,661,734 23,807,677 Book value per common share (GAAP) $ 34.79 $ 34.30 $ 32.32 $ 32.33 $ 32.25 $ 30.90 $ 29.58 $ 27.15 Tangible book value per common share (non-GAAP) 29.24 28.68 26.78 26.71 26.53 25.09 23.41 25.05 28 RECONCILIATION OF NON-GAAP FINANCIAL MEASURES DOLLARS IN THOUSANDS, EXCEPT PER SHARE AMOUNTS, UNAUDITED

ORIGIN BANCORP, INC. _______ AFS - Available for sale MSA - Metropolitan Statistical Area ALCL - Allowance for loan credit losses NIE - Noninterest expense CAGR - Compound annual growth rate NIM - Net interest margin C&I - Commercial & industrial loans NIM - FTE - Net interest margin, fully tax equivalent CMO - Collateralized mortgage obligations OID AMORTIZATION - Original issue discount amortization CORE DEPOSITS - Total deposits excluding time deposits greater than $250,000, brokered and Certificate of Deposit Account Registry Service deposits OREO - Other real estate owned PTPP - Pre-tax, pre-provision CRE - Commercial real estate loans PTPP ROAA - Pre-tax, pre-provision return on average assets DFW - Dallas/Fort Worth QTD - Quarter-to-date EPS - Earnings per share QoQ - Quarter-over-quarter FDIC - Federal Deposit Insurance Corporation ROAA - Return on average assets FHLB - Federal Home Loan Bank ROAE - Return on average equity GAAP - Generally accepted accounting principles ROATCE - Return on average tangible common equity LOC - Letters of credit SOFR - Secured Overnight Financing Rate LHFI - Loans held for investment YoY - Year over year MBS - Mortgage-backed securities YTD - Year-to-date GLOSSARY OF TERMS 29

ORIGIN BANCORP, INC. _______ 30 PRESENTATION NOTES (1) Excludes Treasury/wholesale deposits of $153.7 million at March 31, 2026. (2) Excludes mortgage warehouse LOC. (3) Excludes notable items. (4) Data obtained from Office of the Texas Governor (gov.texas.gov), Bureau of Labor Statistics (bls.gov), Baldwin County Economic Development Council (baldwineda.com), Florida's Great Northwest (floridasgreatnorthwest.com), Bureau of Transportation Statistics (bts.gov) and Port of Mobile, Alabama Port Authority (alports.com). (5) As used in this presentation, PTPP earnings, PTPP ROAA, ROATCE, tangible book value per common share, and tangible common equity to tangible assets are either non-GAAP financial measures or use a non-GAAP contributor in the formula. For a reconciliation of these alternative financial measures to their comparable GAAP measures, see slides 26-28 of this presentation. (6) Core deposits are total deposits excluding time deposits greater than $250,000, brokered and Certificate of Deposit Account Registry Service deposits. (7) Origin Bancorp, Inc. and KBW Nasdaq Bank cumulative total shareholder return assumes $100 invested on December 31, 1996, and any dividends are reinvested. Data for Origin Bancorp, Inc. cumulative total shareholder return prior to May 9, 2018, is based upon private stock transactions and is not reflective of open market trades. (8) Data obtained from The United States Census Bureau (census.gov). Count is as of most recent practicable date. (9) Excludes Paycheck Protection Program (“PPP”) loans for 2020 and 2021. (10) Excludes Treasury/wholesale deposits for all periods presented. Periods at or prior to December 31, 2023, were adjusted to include mortgage warehouse deposits in our DFW market. (11) The DFW and Houston markets have been adjusted to include $108.0 million of deposits in total that were sold on December 31, 2024, and immediately repurchased on January 2, 2025. The DFW and Houston markets have been adjusted to include $61.5 million of deposits in total that were sold on December 31, 2025, and immediately repurchased on January 2, 2026. (12) Does not include loans held for sale. (13) The ALCL to total LHFI, adjusted is calculated by excluding the ALCL for mortgage warehouse LOC from the total LHFI ALCL in the numerator and excluding the mortgage warehouse LOC from the LHFI in the denominator. Due to their low-risk profile, mortgage warehouse LOC require a disproportionately low allocation of the ALCL. (14) The accumulated other comprehensive loss primarily represents the unrealized loss, net of tax benefit, of available for sale securities and is a component of equity. (15) Floating rate loans typically reprice monthly, while variable rate loans reprice based upon the terms defined within the adjustable rate loan agreement specific to their loan contract. (16) Uses total deposits costs for the month ended August 31, 2024, as the cycle starting point. (17) Projection is based upon March 31, 2026, time deposit balances. (18) Argent investment income and limited partnership investment (loss) income are components of equity method investment (loss) income on the face of the income statement. (19) March 31, 2026, capital ratios are estimated. (20) Sub-debt redeemed includes the amortization of the original issue discount (“OID”) and fair value mark. $34,000 and $35,000 of the sub-debt OID and fair value mark amortization is included in the quarters ended 2Q25 and 3Q25, respectively. (21) The diluted EPS impact is calculated using a 21% effective tax rate. The total of the diluted EPS impact of each individual line item may not equal the calculated diluted EPS impact on the total notable items due to rounding. (22) Operating expenses related to strategic Optimize Origin initiatives are expected to be immaterial and, accordingly, will no longer be separately tracked beginning with the quarter ended March 31, 2026. Operating expenses of $51,000 related to strategic Optimize Origin initiatives for the quarters ended December 31, 2025, included sub-lease income of $40,000 which was recorded in noninterest income on the face of the income statements.