Enterprise Financial Services (EFSC) 8-K Agenda Topics Talent 2017 & 2018 Q1 Review Strength 2017 & 2018 Q1 Financial Performance Passion Our Vision and Beyond 2

Annual Shareholder Meeting May 2, 2018

Agenda Topics Talent 2017 & 2018 Q1 Review Strength 2017 & 2018 Q1 Financial Performance Passion Our Vision and Beyond 2

Talent: 2017 & 2018 Q1 Review 3 Scott Goodman, President, Enterprise Bank & Trust

4 Recognition 2017 Community Bankers Cup winner by Raymond James #14 out 161 banks by Bank Director Ranked #49 on S&P’s Global Market Intelligence Top 100 Bank List 5 Greenwich Excellence Awards Financial Innovation Award from Everfi Healthiest Workplace from Interactive Health BOTTOM LINE? We’re nationally ranked in the top 10% for banks our size.

St. Louis 19 Locations 4 Commercial Hubs 5

Kansas City 7 Locations 1 Commercial Hub 6

7 Phoenix 2 Locations 1 Commercial Hub

Specialized Market Segments 8

Credit Metrics for Portfolio Loans Net Charge-offs (1) Q1 2018 EFSC PEER(1) NPA’S/ASSETS 0.30% 0.49% NPL’S/LOANS 0.38% 0.62% ALLL/NPL’S 254.0% 145.2% ALLL/LOANS 0.98% 0.99% (1) Peer data as of 12/31/2017 (source: SNL Financial) 9

10 Customer Focus Key Drivers of Loyalty Enterprise Clients Market Score (non-clients) Ease of Doing Business 79 56 Bank I Trust 93 59 Values Long-Term Relationship 84 49 Provides Innovative Solutions & Ideas 60 39 Anticipates Future Opportunities & Risks 55 38 Understands My Industry 61 43 65 NPS N E T P R O M O T E R S C O R E - A MEASURE OF CLIENT SATISFACTION INDUSTRY AVERAGE: 34 (source: Greenwich)

Our talent leads to… Talent Strength 11

Strength: Financial Performance Keene Turner, Chief Financial and Operating Officer, Enterprise Financial Services Corp

13 Core EPS Growth* Note: * A Non-GAAP Measure

14 2017 Core EPS Drivers* Note: * A Non-GAAP Measure, Refer to Appendix for Reconciliation

Core Net Interest Income Trend* Note: * A Non-GAAP Measure, Refer to Appendix for Reconciliation 15

Continued Leverage of Operating Expenses* Note: * A Non-GAAP Measure, Refer to Appendix for Reconciliation 16

17 Financial Scorecard Q1 2018 Compared to Q1 2017 21% Drive Net Interest Income Growth in Dollars with Favorable Loan Growth Trends 11 bps Defend Net Interest Margin 2% Achieve Further Improvement in Operating Leverage Continued Growth in Core EPS42% Enhance Deposit Levels to Support Growth6% CORE EPS: $0.84 ROAA: 1.49%

18 Capital Management

19 Shareholder Value Note: Index=SNL U.S. Bank $5B-$10B, as of 03/31/18 $10,000 invested in 2013 = $36,600 at the end of 2017 65% more than the bank index

Our marketplace strength is not possible without… Talent Strength Passion 20

Passion: Our Vision Jim Lally, President and CEO, Enterprise Financial Services Corp

Our Vision To have a company where our associates are proud, our customers find easy to navigate, our investors value and our communities flourish. 4

Let’s 23 Celebrate!

25 Reconciliation of Non-GAAP Financial Measures ($ in thousands, except per share data) March 31, 2018 March 31, 2017 December 31, 2017 December 31, 2016 December 31, 2015 December 31, 2014 CORE PERFORMANCE MEASURES Net interest income $ 46,171 $ 38,642 $ 177,304 $ 135,495 $ 120,410 $ 117,368 Less: Incremental accretion income 766 1,075 7,718 11,980 12,792 18,930 Core net interest income 45,405 37,567 169,586 123,515 107,618 98,438 Total noninterest income 9,542 6,976 34,394 29,059 20,675 16,631 Less: Gain on sale of other real estate from non-core acquired loans — — (6) 1,565 107 445 Less: Other income from non-core acquired assets 1,013 — — 621 — — Less: Gain on sale of investment securities 9 — 22 86 23 — Less: Change in FDIC loss share receivable — — — — (5,030) (9,307) Less: Closing fee — — — — — 945 Core noninterest income 8,520 6,976 34,378 26,787 25,575 24,548 Total core revenue 53,925 44,543 203,964 150,302 133,193 122,986 Provision for portfolio loan losses 1,871 1,533 10,764 5,551 4,872 4,409 Total noninterest expense 29,143 26,736 115,051 86,110 82,226 87,463 Less: Merger related expenses — 1,667 6,462 1,386 — — Less: Other expenses related to non-core acquired loans 14 123 240 1,094 1,558 2,953 Less: Facilities disposal charge — — 389 1,040 — 1,004 Less: Executive severance — — — 332 — — Less: FDIC loss share termination — — — — 2,436 — Less: FDIC clawback — — — — 760 1,201 Less: FHLB prepayment penalty — — — — — 2,936 Less: Other non-core expenses — — — 41 — — Core noninterest expense 29,129 24,946 107,960 82,217 77,472 79,369 Core income before income tax expense 22,925 18,064 85,240 62,534 50,849 39,208 Total income tax expense 3,778 5,106 38,327 26,002 19,951 13,871 Less: Income tax expense from deferred tax asset revaluation1 — — 12,117 — — — Less: Other non-core income tax expense2 438 190 882 4,705 2,893 706 Core income tax expense 3,340 4,916 25,328 21,297 17,058 13,165 Core net income $ 19,585 $ 13,148 $ 59,912 $ 41,237 $ 33,791 $ 26,043 Core diluted earnings per share $ 0.84 $ 0.59 $ 2.58 $ 2.03 $ 1.66 $ 1.29 Core return on average assets 1.49% 1.17% 1.20% 1.09% 1.00% 0.82% Core return on average common equity 14.34% 11.29% 11.26% 11.10% 10.08% 8.63% Core return on average tangible common equity 18.64% 13.75% 14.46% 12.18% 11.22% 9.77% Core efficiency ratio 54.02% 56.01% 52.93% 54.70% 58.17% 64.53% NET INTEREST MARGIN TO CORE NET INTEREST MARGIN (FULLY TAX EQUIVALENT) Net interest income 46,386$ 39,147$ 179,114$ 137,261$ 122,141$ 119,002$ Less: Incremental accretion income 766 1,075 7,718 11,980 12,792 18,930 Core net interest income 45,620$ 38,072$ 171,396$ 125,281$ 109,349$ 100,072$ Average earning assets 4,948,875$ 4,259,198$ 4,611,671$ 3,570,186$ 3,163,339$ 2,921,978$ Reported net interest margin 3.80% 3.73% 3.88% 3.84% 3.86% 4.07% Core net interest margin 3.74% 3.63% 3.72% 3.51% 3.46% 3.42% For the Year ended 1Deferred tax asset revaluation associated with U.S. corporate income tax reform. 2Other non-core income tax expense calculated at 24.7% of non-core pretax income for 2018. For 2017, the calculation is 38.0% of non-core pretax income plus an estimate of taxes payable related to non-deductible JCB acquisition costs. For the Quarter ended