Terms of the Proposed OfferingIssuer Enterprise Financial Services Corp Security Subordinated Notesdue 2030 Rating BBB by Kroll Offering Type SEC Registered Amount $50 Million Rate Structure Fixed-to-Floating Rate Maturity 10Years Call Date 5 Years Covenants Consistent with regulatory limitationsof Tier 2 Capital Use of Proceeds General corporate purposes, which may include repayment or redemption of outstanding indebtedness, the payment of dividends, providing capital to support our organic growth or growth through strategic acquisitions, capital expenditures, financing investments, repurchasing shares of our common stock, and for investments in the Bank as regulatory capital Book-Running Manager Co-Manager 3

About Enterprise Financial Services Corp

5 Enterprise Financial Services Corp Company Overview Financial Highlights Note: Financial metrics as of or for the quarter ended March 31, 2020 1)See Appendix for reconciliation of non-GAAPfinancial measures •NASDAQ: EFSC •Headquartered in Clayton, MO •Within the St. Louis, MO MSA •Enterprise Bank & Trust founded in 1988; EFSC founded in 1995 •Total assets of $7.5 billion, as of March 31, 2020 •37full-service branches, located within Missouri, New Mexico, Arizona and Kansas FranchiseDollars in millionsTotal Assets$7,501Gross Loans$5,458Total Deposits$5,990Loan / Deposit Ratio91.1%Tangible Common Equity ¹$612Total Equity$846Total Equity / Total Assets11.28%Tang. Common Equity / Tang. Assets ¹8.42%Tier 1 Leverage Ratio9.94%CET1 Ratio9.58%Tier 1 Capital Ratio11.03%Total RBC Ratio12.85%Core Net Interest Margin ¹3.71%Cost of Deposits0.68%Return on Avg. Assets0.70%Return on Avg. Common Equity5.98%Return on Avg. Tangible Common Equity ¹8.22%Core Efficiency Ratio ¹51.2%Asset QualityNPAs / Assets0.56%Balance SheetCapitalProfitability

6 Four Urban MarketsSt. Louis Kansas City New Mexico Phoenix Loans¹ $2.6 billion $832 million $636 million $383 million Total Deposits ($000)¹ $3.7billion $826 million $1.0 billion $233 million Branches ² 21 7 6 2 Deposit Market Share³ 4th/ 4.59% 16th/ 1.29% 7th/ 3.23% 30th/ 0.17% Primary Competitors US Bancorp Bank of America Commerce UMB Commerce Bank of America Wells Fargo Bank of America BOK Financial Corp JPMorgan Chase Wells Fargo Bank of America

The Enterprise Story 7 Our Mission Guiding people to a lifetime of financial success Our Vision To be a company where our associates are proud to work, that delivers ease of navigation to our customers and value to our investors, while helping our communities flourish7

Executive Leadership TeamJames B. LallyKeene S. Turner, CPAPresident & Chief Executive Officer, EFSCEVP & Chief Financial Officer, EFSCYears at Enterprise: 16 │ Years in Banking: 28Years at Enterprise: 6 │ Years in Banking: 20Scott R. GoodmanDoug BauchePresident, Enterprise Bank & TrustChief Credit Officer, Enterprise Bank & TrustYears at Enterprise: 17 │ Years in Banking: 31Years at Enterprise: 20 │ Years in Banking: 30Bauche is Chief Credit Officer of Enterprise Bank & Trust and chair of the company’s Executive Credit Committee. His career started with Mercantile Bancorporation in Springfield, Missouri in 1990 as a commercial lender. In 1994, he transferred with Mercantile to the St. Louis area to assist with the acquisition and integration of a commercial bank. Through 1997, Bauche continued to assist Mercantile with numerous other bank acquisitions. In 1997, Bauche was promoted within Mercantile’s community bank credit administration, which oversaw all large (>$3 million) commercial credit origination in Mercantile’s community banking markets throughout Missouri, Arkansas, Illinois and Iowa. In 2000, Bauche joined Enterprise Bank & Trust, as a Vice President of commercial lending, where he developed a substantial portfolio of middle market C&I clients. In 2009, he was promoted to lead the bank’s St. Charles Region and subsequently assumed the chairperson’s responsibility of the St. Louis Regional Credit Committee and became a voting member of the Executive Credit Committee. In 2014, Doug was promoted to President of Enterprise Bank’s St. Louis Region. Doug is a 1992 graduate from Missouri State University. He is a member of the Lewis & Clark Young-Presidents Organization. He serves as a member of the BJC St. Peters & Progress West Hospital Foundation Board.Jim Lally is President and CEO of Enterprise Financial Services Corp (Nasdaq: EFSC). He is a passionate advocate for the company’s mission to ensure a lifetime of financial success through unmatched client attention, education and philanthropy. Throughout his career, Jim has helped EFSC achieve record financial results, increased market share, and industry-leading customer satisfaction. Before being named CEO in May of 2017, he served as President of EFSC, Director of Fee Businesses and Director of Commercial Banking for Enterprise Bank & Trust, the company’s principal subsidiary. Before joining EFSC, Jim worked in various commercial banking capacities with U.S. Bank and Commerce Bank.A native of St. Louis, Jim received his MBA from the University of Missouri–St. Louis and his Bachelor of Science degree in finance from Saint Louis University. In June of 2016, Jim completed The Executive Program at the Darden School of Business University of Virginia.Keene previously served at National Penn Bancshares, Inc. in Pennsylvania as Executive Vice President and Chief Accounting Officer. Prior to National Penn, Turner was a vice president at the investment banking firm Griffin Financial Group, where he advised financial institutions on mergers, acquisitions and other strategic matters. He is a CPA, with public accounting experience at Ernst & Young, LLP.Turner is a summa cum laude graduate of Albright College in Reading, Pennsylvania with a Bachelor of Science Degree in Economics, Accounting and Business Administration.In his role as President of Enterprise Bank & Trust, Scott directs Enterprise’s commercial, business and consumer banking channels as well as the various fee business lines including wealth management in all three of its markets. He also serves on the Board of Enterprise Bank & Trust and on Enterprise Financial’s executive management committee.Scott has held numerous positions since joining Enterprise in 2003. Prior to Enterprise, Scott held various positions at US Bank and Boatman’s Bank. He has over 30 years of professional experience in financial management and banking.Goodman received his BSBA in Accounting/Finance from Rockhurst University in Kansas City, MO in 1985 and his MBA from St. Louis University in 1989.8

Business Line Overview Business and Personal Banking Services •Lending services include C&I, CRE, real estate construction and development, residential real estate, and consumer loans •Wide variety of deposit products •Complete suite of treasury management and international trade services •Tax credit brokerage activities, consisting of the acquisition of Federal and State tax credits and the sale of these tax credits to clients •Enterprise Trust provides financial planning, estate planning, investment management, and trust services to businesses, individuals, institutions, retirement plans, and non-profit organizations Specialized Lending and Product Niches •Support mid-market company mergers and acquisitions in many domestic markets, marketing directly to targeted private equity firms, principally SBICs, and provide primarily senior debt financing to portfolio companies Enterprise Value Lending / Senior Debt Financing Life Insurance Premium Finance •Acquire 10-year streams of Missouri state tax credits from affordable housing development funds and sell the tax credits to clients and other individuals for tax planning purposes •The Company has a minority ownership in a partnership that acquires, invests and sells, state low income housing tax credits; Enterprise lends the partnership money with 6 -12 year terms and receives interest income and fee income when projects close and when credits are sold Tax Credit Related Lending Tax Credit Brokerage Agriculture Enterprise Aircraft Finance •Specialize in financing whole life insurance premiums utilized in high net worth estate planning, through relationships with boutique estate planners throughout the United States •Secured lender on affordable housing projects funded through the use of federal and state low income housing tax credits •Provide leveraged and other loans on projects funded through the U.S. Department of the Treasury Community Development Financial Institution (“CDFI”) New Markets Tax Credit Program •Have been selected to distribute New Markets Tax Credits and continue to participate in the application process, as well as serve as a secured lender to other allocatees •Provide specialized financing and leasing solutions for the acquisition of owner-operator fixed and rotor wing aircraft including aircraft used as a primary business asset as well as short-term floor plans •Engage in lending to agricultural businesses, including farms, for both real estate loans and operational loans principally in Missouri, Illinois, and Kansas •Agriculture loans are secured with equipment, cattle, crops or other non-real property and at times the underlying real property 9

Financial Summary

$6.9 $7.2 $7.3 $7.3 $7.5 $6.6 $6.7 $6.8 $6.9 $7.0 $7.1 $7.2 $7.3 $7.4 $7.5 $7.6 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Total Assets ($B) Balance Sheet Metrics Total Assets Total Deposits Gross Loans$5.0 $5.1 $5.2 $5.3 $5.5 $4.7 $4.8 $4.9 $5.0 $5.1 $5.2 $5.3 $5.4 $5.5 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Gross Loans ($B) $5.5 $5.6 $5.6 $5.8 $6.0 $5.3 $5.4 $5.5 $5.6 $5.7 $5.8 $5.9 $6.0 $6.1 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Total Deposits ($B) 91% 93% 93% 92% 91% 80% 82% 84% 86% 88% 90% 92% 94% 96% 98% 100% 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Loans / Deposits (%) Loans / Deposits Our Growth Strategy is First and Foremost Client Relationship Driven11

Return on Average Assets Return on Average Equity1.10% 1.05% 1.60% 1.58% 0.70% 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 ROAA (%) 9.89% 9.09% 13.66% 13.43% 5.98% 12.93% 12.92% 19.08% 18.54% 8.22% 0.00% 4.00% 8.00% 12.00% 16.00% 20.00% 24.00% 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 ROAE (%) ROATCE (%) ¹ Net Interest Margin Efficiency Ratio3.87% 3.86% 3.81% 3.68% 3.79% 3.79% 3.80% 3.69% 3.64% 3.71% 3.00% 3.25% 3.50% 3.75% 4.00% 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Net Interest Margin (%) Core Net Interest Margin (%) ¹ 64.7% 66.6% 49.9% 50.5% 50.4% 54.1% 53.3% 51.7% 50.7% 51.2% 30.0% 40.0% 50.0% 60.0% 70.0% 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Efficiency Ratio (%) Core Efficiency Ratio (%) ¹ Earnings and Profitability Metrics 1)See Appendix for reconciliation of non-GAAPfinancial measures Attractive Core Performance Measures12

2.0 2.7 2.7 2.6 2.5 2.9 3.4 3.2 3.3 3.1 1.8 2.4 2.5 2.4 2.2 0.2 0.6 1.2 3.4 2.0 2.3 2.9 4.0 2.7 3.6 $9.2 $12.0 $13.6 $14.4 $13.4 $0.0 $3.0 $6.0 $9.0 $12.0 $15.0 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Wealth Management Deposit Services Charges Card Services Tax Credit Income Other Noninterest Income and Noninterest Expense Note: Dollars in millions Noninterest Income Noninterest Expense7.3 10.3 0.4 19.4 20.7 20.8 20.4 21.7 2.6 3.2 3.2 3.5 3.3 10.5 14.9 13.8 14.5 13.7 $39.8 $49.1 $38.2 $38.4 $38.7 $0.0 $10.0 $20.0 $30.0 $40.0 $50.0 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Merger Expenses Compensation and Benefits Occupancy Other •Other noninterest income is composed of swap fees, CDE, mortgage, non-core acquired income and miscellaneous •Noninterest income accounted for approximately 18% of 2020Q1 total revenues •Other noninterest expense is composed of adjustments in ORE, core deposit amortization, card processing costs, employee support fund contribution, FDIC assessment costs and miscellaneous 13

Historical Capital Ratios 1)See Appendix for reconciliation of non-GAAPfinancial measures TCE / TA ¹ Tier 1 Leverage Ratio Tier 1 Capital Ratio Total Risk Based Capital Ratio8.35% 8.43% 8.54% 8.89% 8.42% 5.00% 6.00% 7.00% 8.00% 9.00% 10.00% 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 TCE / TA (%) 11.43% 9.81% 9.83% 10.05% 9.94% 8.00% 9.00% 10.00% 11.00% 12.00% 13.00% 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Leverage Ratio (%) 11.25% 11.06% 11.17% 11.40% 11.03% 8.00% 9.00% 10.00% 11.00% 12.00% 13.00% 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Tier 1 Capital Ratio (%) 12.86% 12.62% 12.72% 12.90% 12.85% 10.00% 11.00% 12.00% 13.00% 14.00% 15.00% 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Total Capital Ratio (%)14

Loan Diversification Note: Financial data as of March 31, 2020 1)Dollars in millions Loan Composition by Product Type Total Loans by Business Unit ¹ Loan Composition by Industry Type CRE34.9% Construction8.2% Residential6.3% Consumer2.1% EVL8.1% LIPF9.1% Tax Credit6.5% Agriculture3.1% C&I21.7% Real Estate/ Rental/Leasing 28.9% Finance and Insurance 16.7% Manufacturing7.8% Other Services7.0% Wholesale Trade6.0% Accommodation & Food Service5.4% Other Services28.2% Total $5.5Billion Concentration Ratios CRE / Bank Level Total Risk Based Capital: 257% ADC / Bank Level Total Risk Based Capital: 59% Total $5.5Billion 2019Q1 2019Q4 2020Q1 2019Q1 2019Q4 2020Q1 2019Q1 2019Q4 2020Q1 2019Q1 2019Q4 2020Q1 2019Q1 2019Q4 2020Q115

Loan Summary Note: Dollars in millions 1)Specialized categories may include a mix of C&I, CRE, Construction and land development, or Consumer & Other loans 2020Q1 2019Q4 2019Q1 C&I –General $1,186 $1,187 $1,129 CRE, Investor Owned –General 1,319 1,290 1,183 CRE, Owner Occupied –General 585 582 576 Enterprise Value Lending¹ 441 429 440 Life Insurance Premium Financing¹ 497 473 441 Residential Real Estate –General 346 366 433 Construction and Land Development–General 446 429 345 Tax Credits¹ 354 294 235 Agriculture¹ 168 140 126 Consumer & Other –General 116 124 109 Total Loans $5,458 $5,314 $5,017

Loan Portfolio: C&I and Commercial Real Estate by Industry Note: Financial data as of March 31, 2020 Investor Owned CRE Loans by Industry Owner Occupied CRE Loans by Industry C&I Loans by Industry Finance and Insurance 34.7% Manufacturing 14.1% Wholesale Trade9.6% Professional Services7.0% Real Estate/ Rental/Leasing5.7% Retail Trade4.5% Other24.4% Total $2.5Billion Real Estate/Rental/Leasing 17.6% Agricultural 16.9% Retail Trade15.3% Wholesale Trade7.8% Manufacturing7.8% Construction6.4% Other28.2% Real Estate/ Rental/Leasing 77.5% Accommodation, Food Service 10.5% Health Care, Social Assistance6.1% Other5.9% Total $1.3 Billion Total $721 Million$2,227 $2,265 $2,303 $2,361 $2,469 $0 $500 $1,000 $1,500 $2,000 $2,500 $3,000 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 C&I Loans ($M)17

Loan Portfolio: Enterprise Value Lending and Hospitality Note: Financial data as of March 31, 2020 Hospitality Enterprise Value Lending (EVL) Manufacturing 34.4% Professional Technical 15.1% Wholesale Trade14.5% Waste Management10.1% Construction4.8% Arts & Entertainment4.0% Other17.1% Total $441 Million •40% of EVL loans are sourced in the Midwest, 21% in the Southeast, 16% in the Northeast, 12% in the Southwest and 11% in the West •There are 181 loans within this portfolio with an average balance of $2.4 million •100% of the portfolio was internally reviewed to identify businesses most at risk for impacts from COVID-19; external review contracted for 2020Q2 •90% of the portfolio is sponsored by a Small Business Investment Company (“SBIC”) licensed by the SBA •As of May 5, 2020, 60% of the portfolio had been approved for PPP funding •30% of the portfolio is secured by borrowing bases •Top 10 sponsors make up half of the EVL portfolio •Average 8-year relationship and 10 deals Total $358 Million Commercial Real Estate 55.1% Construction 22.1% EVL4.9% Tax Credits3.9% C&I14.0% •By subsector, 61% of the portfolio falls within hotels and campgrounds, 21% are food and drink services and 18% are amusement and recreation •There are 273 loans within this portfolio with an average balance of $1.3 million •Internally reviewed 99% of hotel portfolio and 71% of restaurant portfolio •Average LTV between 60-62% •86% of committed exposure for hotels and 40% for restaurants have full recourse •42% of the restaurant portfolio is represented by two borrowers, both of which have been approved for PPP loans 18

Loan Portfolio: Energy-Related and Agricultural Note: Financial data as of March 31, 2020 Agricultural Energy-Related Hog & Pig Farming 28.3% Corn Farming 21.5% Beef Cattle18.3% Dairy Cattle5.9% Soybean Farming5.6% Misc Crop10.0% Other10.4% Total $168 Million •80% of the portfolio is attributable to CRE –Owner Occupied; 20% is attributable to C&I •There are 170 loans within this portfolio with an average balance of $1.0 million •Experienced farming operations, well secured by •Accounts Receivable •Livestock •Real Estate •Diversified portfolio generally supported by production contracts and hedge strategies C&I 53.6% Construction 5.7% CRE24.2% Residential/ Consumer0.7% EVL12.4% Aircraft3.4% Merchant Wholesaler 31.7% Manufacturing 22.4% Gas Stations15.3% Transportation/Warehousing10.4% Utilities7.6% Other9.2% Professional3.4% •There are 86 loans within this portfolio with an average balance of $1.6 million •Internally reviewed 82% of portfolio •76% of committed exposure has full recourse •Diversified with distribution, wholesaling, rail transportation, pipe coating and convenience stores with gas pumps By Type By Subsector Total $140 Million Total $140 Million19

Aircraft Finance 53.5% CRE-Owner Occupied 43.8% C&I2.7% Retail Trade 75.5% Real Estate, Rental, Leasing 6.3% Transportation & Warehousing4.8% Manufacturing4.4% Other9.0% Loan Portfolio: Auto Dealer / Aircraft Lending and Secured by Marketable Securities Note: Financial data as of March 31, 2020 Secured by Marketable Securities Auto Dealer / Aircraft Lending •There are 100 loans within this portfolio with an average balance of $1.7 million •Internally reviewed 81% of portfolio •Auto Dealers are primarily secured by real estate, i.e. no floor-plan loans •90% of committed exposure has full recourse •Aircraft lending, $93.2 Million •Advance rate 70-75% of retail value •Personal recourse from owners, with a typical short-term 6-month facility •There are 241 loans within this portfolio with an average balance of $2.5 million •Reviewed 80% of the non-LIPFportfolio •Currently showing a minimal margin shortfall •LIPFPortfolio •The life insurance policies financed have an earnings floor of 0%, and therefore cannot lose value •Enterprise does not finance variable policies that may lose value Life Insurance Premium Finance 81.6% CRE-Investor Owned 1.9% Other5.7% C&I9.6% Agricultural1.2% Finance & Insurance 82.6% Management 6.0% Other11.4% By Type By Subsector Total $175 Million Total $175 Million Total $609 Million Total $609 Million20

Summary Asset Quality Non-Performing Assets Non-Performing Loans Net Charge-Offs Loan Loss Reserves$16.4 $30.4 $24.1 $32.8 $42.3 0.24% 0.42% 0.33% 0.45% 0.56% 0.00% 0.10% 0.20% 0.30% 0.40% 0.50% 0.60% $0.0 $5.0 $10.0 $15.0 $20.0 $25.0 $30.0 $35.0 $40.0 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 NPAs ($M) NPAs / Assets (%) $9.6 $19.8 $15.6 $26.4 $37.2 0.19% 0.39% 0.30% 0.50% 0.68% 0.00% 0.10% 0.20% 0.30% 0.40% 0.50% 0.60% 0.70% 0.80% $0.0 $5.0 $10.0 $15.0 $20.0 $25.0 $30.0 $35.0 $40.0 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 NPLs ($M) NPLs / Loans (%) $43.1 $43.8 $44.6 $43.3 $92.2 0.86% 0.85% 0.85% 0.81% 1.69% 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% $0.0 $10.0 $20.0 $30.0 $40.0 $50.0 $60.0 $70.0 $80.0 $90.0 $100.0 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 LLR ($M) LLR / Loans (%) $1.8 $1.0 $1.1 $2.5 $1.2 0.16% 0.08% 0.08% 0.19% 0.09% 0.00% 0.05% 0.10% 0.15% 0.20% 0.25% $0.0 $0.5 $1.0 $1.5 $2.0 $2.5 $3.0 $3.5 $4.0 $4.5 $5.0 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 NCOs ($M) NCOs / Average Loans (%)21

Deposit Mix Note: Financial data as of March 31, 2020; dollars in millions 1)Excludes reciprocal deposits Deposit Composition Cost of Total Deposits Brokered Deposits ¹$519.1 $574.4 $501.4 $519.6 $593.3 9.37% 10.33% 8.91% 9.00% 9.91% 8.00% 8.50% 9.00% 9.50% 10.00% 10.50% $0.0 $100.0 $200.0 $300.0 $400.0 $500.0 $600.0 $700.0 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Brokered Deposits ($M) As a Percent of Total Deposits (%) 1.02% 0.94% 0.94% 0.81% 0.68% 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 2019Q1 2019Q2 2019Q3 2019Q4 2020Q1 Cost of Deposits (%) Noninterest-bearing 22.6% Interest-bearing transaction 23.2% Money market and savings41.4% Brokered certificates of deposit2.8% Other certificates of deposit9.9%Noninterest-bearing $1,355 Interest-bearing transaction 1,390 Money market and savings 2,480 Brokered certificates of deposit 171 Other certificates of deposit 595 Total $5,990 Total $6.0 Billion22

Securities Portfolio Note: Financial data as of March 31, 2020 •The following table presents the amortized cost, gross unrealized gains and losses and fair value of securities available for sale and held to maturity: •At March 31, 2020, there were no holdings of securities of any one issuer in an amount greater than 10% of shareholders’ equity, other than U.S. Government agencies and sponsored enterprises •The agency mortgage-backed securities are all issued by U.S. Government agencies and sponsored enterprises Gross Gross Allowance Amortized Unrealized Unrealized for Credit Fair Cost Gains Losses Losses Value Security Type ($000) ($000) ($000) ($000) ($000) Available-for-sale securities: Obligations of U.S. Government-sponsored enterprises $9,960 $270 -- -- $10,230 Obligations of states and political subdivisions 243,863 10,373 (205) -- 254,031 Agency mortgage-backed securities 863,698 23,465 (496) -- 886,667 U.S. Treasury bills 9,973 613 -- -- 10,586 Total securities available for sale $1,127,494 $34,721 ($701) -- $1,161,514 Held-to-maturity securities: Obligations of states and political subdivisions $11,688 $153 -- ($1) $11,840 Agency mortgage-backed securities 44,720 1,924 -- -- 46,644 Corporate debt securities 122,827 162 (3,090) (302) 119,597 Total securities held to maturity $179,235 $2,239 ($3,090) ($303) $178,081 AFS -Obligations of U.S. Government-sponsored enterprises 0.8% AFS -Obligations of states and political subdivisions 19.0% AFS -Agency mortgage-backed securities66.2% AFS -U.S. Treasury bills0.8% HTM -Obligations of states and political subdivisions0.9% HTM -Agency mortgage-backed securities3.5% HTM -Corporate debt securities8.9% Total $1.3 Billion23

Liquidity Detail Note: Financial data as of March 31, 2020 1)The Bank has unsecured federal funds lines with six correspondent banks Additional Sources of Bank Funding Dividend Capacity Holding Company Detail •Under Federal Reserve policies, financial holding companies may pay cash dividends on common stock only out of income available over the past year if prospective earnings retention is consistent with the organization’s expected future needs and financial condition and if the organization is not in danger of not meeting its minimum regulatory capital requirements •Federal Reserve policy also provides that financial holding companies should not maintain a level of cash dividends that undermines the financial holding company’s ability to serve as a source of strength to its banking subsidiaries •Under Missouri law, the Bank may pay dividends to the Company only from a portion of its undivided profits and may not pay dividends if its capital is impaired •Management believes the projected level of cash at the holding company will be sufficient to meet all projected cash needs Amount Available Type Outstanding ($000) ($000) FHLB $222,000 $591,000 Federal Reserve Bank $0 $1,133,000 Unsecured Federal Funds ¹ $0 $90,000 American Financial Exchange $0 $296,000 Total $222,000 $2,110,000 Amount Available Type Outstanding ($000) ($000) Cash & Due from Banks $13,726 Interest Bearing Balances $6,480 Senior Unsecured Revolving Credit Agreement $0 $25,000 Unsecured Term Loan Agreement $32,857 $0 Subordinated Debt $50,000 $0 Trust Preferred $92,000 $0 Total $174,857 $45,206 24

•Interest rate risk management practices are aimed at optimizing net interest income, while guarding against deterioration that could be caused by certain interest rate scenarios •The Company determines the sensitivity of its short-term future earnings to a hypothetical plus or minus 100 to 300 basis point parallel rate shock through the use of simulation modeling •The following table summarizes the expected impact of interest rate shocks on net interest income •Due to the current level of interest rates, the 300 basis point downward shock scenario is not shown in the table below •At March 31, 2020, the Company had $2.5 billion in variable rate loans that are based on LIBOR and $0.4 million that are based on Prime •Approximately 80% of the LIBOR based loans are indexed to one-month LIBOR •The Company occasionally uses interest rate derivative financial instruments as an asset/liability management tool to hedge mismatches in interest rate exposure indicated by the net interest income simulation described above •to modify the Company’s exposures to interest rate fluctuations and provide more stable spreads between loan yields and the rate on their funding sources Interest Rate Risk Management and Sensitivity Note: As of March 31, 2020Annual Percent ChangeRate Shockin Net Interest Income+ 300 bp9.9%+ 200 bp6.8%+ 100 bp3.5%- 100 bp(6.3)%- 200 bp(7.0)%25

Illustrative Impact of the Proposed Debt Offering 1)Assumes $50.0 million in gross subordinated notes, a 5.50% coupon, variable underwriting fees of 1.50%, fixed offering costs of $300,000 and that proceeds from the offering are invested in cash (0% risk weight); assumes that 0% of net offering proceeds are down-streamed to Enterprise Bank & Trust 2)Excludes one-time merger and restructuring charges; 2020Q1 adjusted pre-tax income excludes provision expense primarily attributable to COVID-19 Dollars in thousandsPro Forma,20162017201820193/31/20203/31/2020 ¹Equity Investment in Subsidiaries$421,336 $632,080 $691,148 $990,654 $976,065 $976,065 Consolidated Equity$387,098 $548,573 $603,804 $867,185 $846,436 $846,436 Double Leverage Ratio108.8%115.2%114.5%114.2%115.3%115.3%Pro Forma,20162017201820193/31/20203/31/2020 ¹Total Deposit Interest$10,841 $17,200 $33,769 $49,856 $47,924 $47,924 Subordinated Debt and TruPS - Outstanding1,894 5,095 5,798 7,507 7,778 7,778 Subordinated Debt - Proposed Offering0 0 0 0 0 2,750 Other Borrowing Interest994 2,940 6,330 9,054 8,761 8,761 Total Interest Expense13,729 25,235 45,897 66,417 64,463 67,213 Pre-Tax Income$74,839 $86,517 $104,577 $116,036 $111,616 $108,866 Interest Coverage (including deposit expense)6.5x4.4x3.3x2.7x2.7x2.6xInterest Coverage (excluding deposit expense)26.9x11.8x9.6x8.0x7.7x6.6xPre-Tax Income, Adjusted ²$76,557 $92,979 $105,848 $134,005 $144,579 $141,829 Interest Coverage (including deposit expense)6.6x4.7x3.3x3.0x3.2x3.1xInterest Coverage (excluding deposit expense)27.5x12.6x9.7x9.1x9.7x8.4xCalculation of Double LeverageCalculation of Interest CoverageFor the Year Ended December 31,For the Year Ended December 31,For the Quarter Ended,For the Twelve Months Ended, 26

Capital Ratios Over Time 1)Assumes $50.0 million in gross subordinated notes, a 5.50% coupon, variable underwriting fees of 1.50%, fixed offering costs of $300,000 and that proceeds from the offering are invested in cash (0% risk weight); assumes that 0% of net offering proceeds are down-streamed to Enterprise Bank & Trust 13.48% 12.21% 13.02% 12.90% 12.85% 13.61% 11.53% 11.36% 12.26% 12.40% 12.37% 12.37% 10.00% 10.50% 11.00% 11.50% 12.00% 12.50% 13.00% 13.50% 14.00% 2016 2017 2018 2019 2020 Q1 Pro Forma ¹Enterprise Financial Services Corp - Total Risk-Based Capital RatioEnterprise Bank & Trust - Total Risk-Based Capital Ratio27

SummaryHighly focused, proven business model Incredibletrack record of commercial loan growth Wide productbreadth and diversifiedincome stream Differentiated competitive lending expertise Thoughtful expansion into Kansas City, Phoenix and New Mexico Strong profitabilitywith a balance sheet positioned for cautious future growth Excellentasset quality; characterized prudentcredit and interest rate risk management Relationship-orienteddistribution and sales approach 28

COVID-19 Pandemic Response Overview

Timeline of Actions: Key Milestones JAN. 23 Discussions begin about virus FEB. 27 Developed COVID-19 Communication and Action Plan Taskforce (CAP Taskforce) MAR. 10 Restricted travel and began canceling in-person meetings and events MAR. 23 Various internal controls adjusted for further contingencies APR. 3 Bank launches SBA Paycheck Protection Program MAR. 30 Bank launches bank sponsored loan deferment programs for clients MAR. 15 Business travel ban and work-from-home mandate MAR. 4 Measures including restricted travel to conferences and social distancing guidelines JAN. 27 COVID-19 communication begins with associates; marketing begins developing messages MONITOR & PLAN ACTIVATION IMPLEMENTATION APR 10 Bank launches associate relief program through foundation MAR. 2 Public Health Emergency Declared 30

Associate Protection & Assistance Regular pay for associates unable to work from home due to COVID-19 relatedillness, caring for ill family member or childcare school closures Health benefits expanded to cover COVID-19 related issues Premium Pay for retail associates working in roles that require direct physical contact with clients or in the office working closely with others Drive thru only (except 5 locations) to reduce potential COVID-19 exposure for associates Virtual recognition program launched for peer-to-peer recognition Weekly 401(k) webinars being conducted for our associates by Wealth Management Promotion of Employee Assistance Program (EAP) benefit for confidential associate support by phone or video 31

Community and Client ProgramsAs a preferred provider of SBA Section 7(a) loans, we provided a live client virtual event to walk through SBA Loan Relief Programs. (2,500 attendees, 500+ webinar downloads) Donated $50,000 in the St. Louis Small Business Relief Fund set up by St. Louis County, City and the Economic Development Partnership. Continuing to provideEnterprise University courses online, for business leaders to have continued access to industry expertise, at no cost, during this time. Offering clients virtual networking, crisis communication education, and access to a growing resource catalog of best practices provided by business leaders across the region. 32

SBA Paycheck Protection Program (PPP) Our Focus We are committed to getting loans for applicants approved and funded as quickly and efficiently as possible. Dedicated team of our most experienced associates focused since April 3 on the PPP loan process Centralized process created with assembly line to isolate touchpoints and process loans efficiently Streamlining the procedures wherever possible Website resources page addresses the most frequently asked question we’re receiving along with frequent updates 33

Appendix

Use of Non-GAAP Financial Measures The Company’s accounting and reporting policies conform to generally accepted accounting principles in the United States (“GAAP”) and the prevailing practices in the banking industry. However, the Company provides other financial measures, such as adjusted EPS, core net interest income, core net interest margin, tangible common equity, core efficiency ratios, ROATCE, adjusted ROAA, adjusted ROAE, and adjusted ROATCE, and the tangible common equity ratio, in this release that are considered “non-GAAP financial measures.” Generally, a non-GAAP financial measure is a numerical measure of a company’s financial performance, financial position, or cash flows that exclude (or include) amounts that are included in (or excluded from) the most directly comparable measure calculated and presented in accordance with GAAP. The Company considers its adjusted EPS, core net interest income, core net interest margin, core efficiency ratio, adjusted ROAA, adjusted ROAE, ROATCE, adjusted ROATCE, and the tangible common equity ratio, collectively “core performance measures,” presented in this earnings release and the included tables as important measures of financial performance, even though they are non-GAAP measures, as they provide supplemental information by which to evaluate the impact of non-core acquired loans, which were acquired from the FDIC and previously covered by loss share agreements, and the related income and expenses, the impact of certain non-comparable items, and the Company’s operating performance on an ongoing basis. Core performance measures include contractual interest on non-core acquired loans, but exclude incremental accretion on these loans. Core performance measures also exclude expenses directly related to non-core acquired loans. Core performance measures also exclude certain other income and expense items, such as merger related expenses, facilities charges, and the gain or loss on sale of investment securities, the Company believes to be not indicative of or useful to measure the Company’s operating performance on an ongoing basis. The attached tables contain a reconciliation of these core performance measures to the GAAP measures. The Company believes that the tangible common equity ratio provides useful information to investors about the Company’s capital strength even though it is considered to be a non-GAAP financial measure and is not part of the regulatory capital requirements to which the Company is subject. The Company believes these non-GAAP measures and ratios, when taken together with the corresponding GAAP measures and ratios, provide meaningful supplemental information regarding the Company’s performance and capital strength. The Company’s management uses, and believes that investors benefit from referring to, these non-GAAP measures and ratios in assessing the Company’s operating results and related trends and when forecasting future periods. However, these non-GAAP measures and ratios should be considered in addition to, and not as a substitute for or preferable to, ratios prepared in accordance with GAAP. In the attached tables, the Company has provided a reconciliation of, where applicable, the most comparable GAAP financial measures and ratios to the non-GAAP financial measures and ratios, or a reconciliation of the non-GAAP calculation of the financial measures for the periods indicated.35

36 CECL Adjustment Balance: March 31, 2020 Net Recoveries Provision for Credit Losses PCDLoans Charged-off ¹ CECL Adoption Balance: December 31, 2019 Note: Dollars in thousands 1)Under the Company’s credit policy, nonaccrual loans less than $100,000 are immediately charged-off

Reconciliation of Non-GAAPFinancial MeasuresQuarter ended ($ in thousands) Mar 31, 2020 Dec 31, 2019 Sep 30, 2019 Jun 30, 2019 Mar 31, 2019 CORE PERFORMANCE MEASURES Net interest income $ 63,368 $ 61,613 $ 63,046 $ 61,715 $ 52,343 Less: Incremental accretion income 1,273 576 2,140 910 1,157 Core net interest income 62,095 61,037 60,906 60,805 51,186 Total noninterest income 13,408 14,418 13,564 11,964 9,230 Less: Other income from non-core acquired assets — 4 1,001 2 365 Less: Gain on sale of investment securities 4 (94 ) 337 — — Less: Other non-core income — — — 266 — Core noninterest income 13,404 14,508 12,226 11,696 8,865 Total core revenue 75,499 75,545 73,132 72,501 60,051 Total noninterest expense 38,673 38,354 38,239 49,054 39,838 Less: Other expenses related to non-core acquired loans 12 33 18 103 103 Less: Merger related expenses — — 393 10,306 7,270 Core noninterest expense 38,661 38,321 37,828 38,645 32,465 Core efficiency ratio 51.21 % 50.73 % 51.73 % 53.30 % 54.06 % NET INTEREST MARGIN TO CORE NET INTEREST MARGIN (TAX EQUIVALENT) Net interest income $ 63,978 $ 62,141 $ 63,483 $ 62,109 $ 52,595 Less: Incremental accretion income 1,273 576 2,140 910 1,157 Core net interest income $ 62,705 $ 61,565 $ 61,343 $ 61,199 $ 51,438 Average earning assets $ 6,791,459 $ 6,704,506 $ 6,604,083 $ 6,453,005 $ 5,510,489 Reported net interest margin 3.79 % 3.68 % 3.81 % 3.86 % 3.87 % Core net interest margin 3.71 3.64 3.69 3.80 3.79 37

Reconciliation of Non-GAAPFinancial MeasuresQuarter ended ($ in thousands) Mar 31, 2020 Dec 31, 2019 Sep 30, 2019 Jun 30, 2019 Mar 31, 2019 SHAREHOLDERS’ EQUITY TO TANGIBLE COMMON EQUITY AND TOTAL ASSETS TO TANGIBLE ASSETS Shareholders’ equity $ 846,436 $ 867,185 $ 846,095 $ 825,501 $ 797,835 Less: Goodwill 210,344 210,344 211,251 211,251 207,632 Less: Intangible assets 24,585 26,076 27,626 29,201 31,048 Tangible common equity $ 611,507 $ 630,765 $ 607,218 $ 585,049 $ 559,155 Total assets $ 7,500,643 $ 7,333,791 $ 7,346,791 $ 7,181,855 $ 6,932,757 Less: Goodwill 210,344 210,344 211,251 211,251 207,632 Less: Intangible assets 24,585 26,076 27,626 29,201 31,048 Tangible assets $ 7,265,714 $ 7,097,371 $ 7,107,914 $ 6,941,403 $ 6,694,077 Tangible common equity to tangible assets 8.42 % 8.89 % 8.54 % 8.43 % 8.35 % 38