PC Connection 8K Investor PresentationSidoti & Company Fall 2018 ConferenceSeptember 27th, 2018 | CNXN 27 Sep 18

Exhibit 99.1

Investor PresentationSidoti & Company Fall 2018 ConferenceSeptember 27th, 2018

2 Disclosures Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved. Safe Harbor StatementUnder the Private Securities Litigation Reform Act of 1995: This presentation contains forward-looking statements that are subject to risks and uncertainties, including, but not limited to, the impact of changes in market demand and the overall level of economic activity and environment, or in the level of business investment in information technology products, competitive products and pricing, product availability and market acceptance, new products, fluctuations in operating results, and the ability of the Company to manage personnel levels in response to fluctuations in revenue, and other risks that could cause actual results to differ materially from those detailed under the caption “Risk Factors” in the Company’s Annual Report on Form 10‑K filed with the Securities and Exchange Commission for the year ended December 31, 2017. More specifically, the statements in this presentation concerning the Company’s outlook and other statements of a non-historical basis (including statements regarding the Company’s ability to grow revenues and increase market share) are forward-looking statements that involve certain risks and uncertainties. Such risks and uncertainties include the ability to realize market demand for and competitive pricing pressures on the products and services marketed by the Company, the continued acceptance of the Company's distribution channel by vendors and customers, continuation of key vendor and customer relationships and support programs, and the ability of the Company to hire and retain qualified sales representatives and other essential personnel. The Company assumes no obligation to update the information in this presentation or revise any forward–looking statements, whether as a result of any new information, future events, or otherwise.Non-GAAP Financial InformationAdjusted EBITDA is a non-GAAP financial measure. This information is included to provide information with respect to the Company’s operating performance and earnings. Non-GAAP measures are not a substitute for GAAP measures and should be considered together with the GAAP financial measures. Our non-GAAP financial measures may not be comparable to other similarly titled measures of other companies.

Our Mission As a leading Global Solutions Provider, we connect our customers with technology that:» Enhances growth » Elevates productivity » Empowers innovation 3 Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

4 Fortune 1000 Global Solutions Provider Founded 1982Employees 2,500Exchange NASDAQSymbol CNXNShares Outstanding 26.9 MillionNet Sales – 2017 $ 2.9 BillionCash Balance – 12/31/17 $ 50 MillionAdjusted EBITDA – 2017 $ 94.0 MillionEPS – 2017 $ 2.04Current Price – 9/20/18 $ 38.74Market Capitalization – 9/20/18 $ 1.035 Billion Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

6 Your IT Partner for Strong Industry Partnerships t We allow you greater access to resources from a successful and proven expert team Microsoft Excellence in Operations Awards:• Double Gold Level, 2017• Gold Level, 2016 & 2015 HPE NSP SLED Partner of the Year, 2017Federal Enterprise Group Partner of the Year, 2015 Lenovo Platinum Data Center Partner, 2017 RedHat Rising Star Partner of the Year, 2017 Dell EMC Healthcare Partner of the Year, 2016Dell Partner of the Year, 2015 Symantec Growth Partner of the Year, 2015 Adobe Reseller Partner of the Year, 2014 VMware Mid-Market Partner of the Year for Americas, 2014 Cisco U.S. Commercial Partner of the Year, 2013 HP MPS Best in Class Award, 2016HP Partner in Excellence Award, 2013 Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

7 Solve Your Toughest IT Challengeswith Expertise You Can Count On 2,500+Employees 860+Account managers 10 YearsAverage tenure 540+Engineering,services, andtechnical staff THETEAM 44,000Hours of trainingannually 2,500+Professional certifications Hundredsof training hoursper engineerevery year THEBUYING POWER 1,600+Technologypartners300,000IT products available225,000+Custom configurations completedevery yearand growing THEEXPERTISE Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

8 Committed to Understanding Customer Needs Social, mobile, new ways to work Self-Driven Outpace competitors, meet customers’ needs Market Driven Regulatory and industry specific demands Governance Driven Cloud, always on, real-time Technology Driven Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

9 Your IT Partner for Emerging Tech Players Flash Storage to tackle explosive data growthHyper-converged Infrastructure for the modern data center, transformed More Choices, More Options, More Relevance Cloud Computing built for cloud power in private, public, and hybrid modelsAdvances in Security provide a comprehensive approach that safeguards against cyber crime and data breaches Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

11 Your IT Partner for Trusted, Proven Methodology Execution Excellence Throughout the Entire Solution Lifecycle Discern—Assess unique requirements for optimal efficiency and cost savings across the entire IT infrastructureDesign—Create flexible and tailored solutions for every business needDeliver—Implement the right technologies for superior ongoing performance, measurable competitive advantage, and manage to maximize ROI throughout the entire IT lifecycle Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

12 Customer-Focused Investments GlobalCapabilities SoftmartSoftware Expertise Launch of NetworkOperations Center New World Class Custom Configuration & Distribution Facility IL and PA Sales Team Expansion Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

13 Simplify the IT Procurement Process Services Management Tool We Have Unique and Valuable AssetsOrganizational Assets Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

14 Partnered with the largest global resellers, System Integrators, and VARs around the world25,000 certified IT professionalsIT services in 174 countriesIndustry recognize global asset disposal services:Built around very stringent IEEE, DoD, and EU standards Global IT Procurement ExpertiseWe Solve Global. We Connect the World. Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

15 2002 Initial Public OfferingNASDAQ: PCCC(now CNXN) Opened Ohio Distribution Centerand IntroducedEverything Overnight ® 2011 2010 2005 Founded National Solutions Provider CorporateIT Systems 1982 1984 2017 Launched Global Alliance with Bechtle 1990 Over 35 Years of Success and Innovation Acquired Softmart & GlobalServe Launched new brand name 2016 Forbes “Americas Most Trustworthy Companies” 2007 & 2008 MacConnectionEstablished 1998 AcquiredMoreDirect, Inc.Enterprise Acquired Amherst Technologies(now Services and Solutions Division) Acquired ValCom(now Services and Solutions Division)Achieved $2B in sales AcquiredComteq Federal,now Public Sector SolutionsAchieved $1B in sales 1999 Celebrated 35 years Pick, Pack & Ship Value Added Reseller IT Services & Solutions 2014 2000 450+ services, technical and engineering staff2,500+ Certifications Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

16 Digital Transformation Data Center Modernization Workplace Transformation Security Transformation Drivers of Growth Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

��17 It All Adds Up to Complete Support for the Complete IT Lifecycle Enhance GrowthGain competitive advantageUtilize proven methodologyEmploy the right solutionsExtract full value of investments Elevate ProductivityModernize data centersSave time and moneyIncrease agilityFocus on needs of business Empower InnovationEnable 360° improvementDeploy modern technologiesOptimize IT operationsSolve challenges for better ROI Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

22 Consistent Revenue GrowthYTD Q2 2017 vs. YTD Q2 2018 7.0% Old vs. Old (6.3%) Old vs. New Old Standard New Standard $1,520,222 Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved. $ in thousands

23 Old Standard New Standard 13.1% 15.3% Consistent Gross Margin GrowthYTD Q2 2017 vs. YTD Q2 2018 Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

24 Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved. Q2 YTD ‘18 operating cash flow of $41.5M vs. a use of ($9.8M) Q2 YTD ’17AR and AP and Accruals grew at 3% and 2%, respectivelyDebt-free169,462 shares repurchased as of Q2 YTD for $4.4MWeighted average cost of repurchases was $25.87 Balance Sheet and Cash Flow Highlights

25 2017 Special Dividend $ 9.1M ($.34 per share) 2016 Special Dividend $ 9.0M ($.34 per share) 2015 Special Dividend $10.6M ($.40 per share) 2014 Special Dividend $10.5M ($.40 per share) 2013 Special Dividend $10.5M ($.40 per share) 2012 Special Dividend $10.1M ($.38 per share) 2011 Special Dividend $10.6M ($.40 per share) Share Repurchases 2011/2012 $11.6M (1.2 million shares) Total cash used in transactions $82.0M Shareholder Transactions2011—2017 Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

26 Statements from August 2nd Q2 Earnings Call Net Sales:" Consistent with industry trends, the IT market is estimated to grow at approximately 3% plus and our goal is to double this rate of growth""We expect Q3's new revenue standard adjustment to be similar to the $78 million adjustment that we saw in Q1"Gross Margin:"We expect our Q3 gross margins to be similar to our 2018 year-to-date levels"SG&A:"We expect SG&A as a percentage of revenue in Q3 to be similar to our 2018 year-to-date levels"Tax Rate:“We expect our rate for the year to be in the range of 27 to 29%" Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

27 Recurring Revenue StreamIncreasing Revenue and ProfitsFinancial StabilityExperienced TeamGlobal Solutions ProviderLarge and Fragmented MarketTechnology Transformations Our DifferenceWhy Invest in Connection Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved.

30 Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved. PC Connection, Inc. & SubsidiariesBusiness Segments – Sales & Margin RECONCILIATION OF CHANGES IN REVENUE STANDARD FOR SEGMENT NET SALES (Unaudited, in thousands) Three Months Ended June 30, ChangeAs Presented ChangePrevious Revenue Standard 2018 2017 Amount Percent Amount Percent Net sales As Presented Impact of NewRevenue Standard Previous Revenue Standard Business Solutions $ 270,042 $ 41,260 $ 311,302 $ 296,420 $ (26,378) (8.9%) $ 14,882 5.0% Enterprise Solutions 301,065 47,977 349,042 302,077 (1,012) (0.3%) 46,965 15.5% Public Sector Solutions 135,463 23,962 159,425 151,295 (15,832) (10.5%) 8,130 5.4% Total $ 706,570 $ 113,199 $ 819,769 $ 749,792 $ (43,222) (5.8%) $ 69,977 9.3% RECONCILIATION OF CHANGES IN REVENUE STANDARD FOR SEGMENT GROSS PROFITS (Unaudited, in thousands) Three Months Ended June 30, ChangeAs Presented ChangePrevious Revenue Standard 2018 2017 Amount Percent Amount Percent Gross profits AsPresented Impact of NewRevenue Standard Previous Revenue Standard Business Solutions $ 47,329 $ 784 $ 48,113 $ 46,277 $ 1,052 2.3% $ 1,836 4.0% Enterprise Solutions 43,256 618 43,874 37,107 6,149 16.6% 6,767 18.2% Public Sector Solutions 16,883 - 16,883 16,286 597 3.7% 597 3.7% Total $ 107,468 $ 1,402 $ 108,870 $ 99,670 $ 7,798 7.8% $ 9,200 9.2% RECONCILIATION OF CHANGES IN REVENUE STANDARD FOR SEGMENT GROSS MARGINS (Unaudited, in thousands) Three Months Ended June 30, ChangeAs Presented ChangePrevious Revenue Standard 2018 2017 Amount Amount Gross margins AsPresented Impact of NewRevenue Standard Previous Revenue Standard Business Solutions 17.5% (207) 15.5% 15.6% 191 (16) Enterprise Solutions 14.4% (180) 12.6% 12.3% 208 29 Public Sector Solutions 12.5% (187) 10.6% 10.8% 170 (17) Total 15.2% (193) 13.3% 13.3% 192 (1)

31 Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved. PC Connection, Inc. & Subsidiaries Income Statement CONDENSED CONSOLIDATED STATEMENTS OF INCOME Three Months Ended June 30, Six Month Ended June 30, (amounts in thousands, except per share data) 2018 2017 2018 2017 Net sales $ 706,570 $ 749,792 $ 1,331,465 $ 1,420,386 Cost of sales 599,102 650,122 1,127,625 1,233,983 Gross profit 107,468 99,670 203,840 186,403 Selling, general and administrative expenses 82,521 77,230 163,421 152,511 Income from operations 24,947 22,440 40,419 33,892 Interest/other expense, net 182 9 298 28 Income tax provision (6,903) (8,864) (11,191) (12,903) Net income $ 18,226 $ 13,585 $ 29,526 $ 21,017 Earnings per common share: Basic $ 0.68 $ 0.51 $ 1.10 $ 0.79 Diluted $ 0.68 $ 0.51 $ 1.10 $ 0.78 Shares used in the computation of earnings per common share: Basic 26,686 26,761 26,760 26,729 Diluted 26,820 26,893 26,868 26,879 Note: Amounts are not restated and represent the amounts recognized under generally accepted accounting principles in place during the relevant reporting period.

32 Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved. PC Connection, Inc. & Subsidiaries Adjusted EBITDA EBITDA AND ADJUSTED EBITDA (amounts in thousands) LTM Ended June 30, (1) ChangeAs Presented ChangePrevious Revenue Standard 2018 2017 Percent Percent As Presented Impact of NewRevenue Standard Previous Revenue Standard Previous Revenue Standard Net income $ 63,366 $ 422 $ 63,788 $ 63,788 $ 47,607 $ 47,607 33% 34% Depreciation and amortization 12,858 - 12,858 12,858 11,359 11,359 13% 13% Income tax expense 21,056 162 21,218 21,218 30,618 30,618 (31%) (31%) Interest expense 121 - 121 121 139 139 (13%) (13%) EBITDA 97,401 584 97,985 97,985 89,723 89,723 9% 9% Special charges (2) 2,695 - 2,695 2,695 3,506 3,506 (23%) (23%) Stock-based compensation 822 - 822 822 788 788 4% 4% Adjusted EBITDA $ 100,918 $ 584 $ 101,502 $ 101,502 $ 94,017 $ 94,017 7% 8% (1) LTM: Last twelve months(2) Special charges in 2017 consist of a fourth quarter one-time bonus paid to all employees except executive officers as well as severance and relocation costs for our Softmart facility incurred in the second quarter 2017. Special charges in last twelve months of 2017 consist of our acquisition of Softmart, the rebranding of the Company, and duplicate costs incurred with the move of our Chicago-area facility.

33 Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved. PC Connection, Inc. & Subsidiaries Balance Sheet CONDENSED CONSOLIDATED BALANCE SHEETS June 30, December 31, 2018 2017 (1) (amounts in millions) ASSETS Current Assets: Cash and cash equivalents $ 68.7 $ 50.0 Accounts receivable, net 464.0 449.7 Inventories, net 107.5 106.8 Prepaid expenses and other current assets 6.3 5.7 Income taxes receivable 0.9 3.9 Total current assets 647.4 616.1 Property and equipment, net 46.0 41.6 Goodwill 73.6 73.6 Other intangibles, net 10.3 11.0 Long-term accounts receivable 1.9 - Other assets 1.8 5.6 Total Assets $ 781.0 $ 747.9 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities: Accounts payable $ 200.9 $ 194.3 Accrued expenses and other liabilities 28.9 31.0 Accrued payroll 23.5 22.7 Total current liabilities 253.3 248.0 Deferred income taxes 16.1 15.7 Other liabilities 1.9 1.9 Total Liabilities 271.3 265.6 Stockholders’ Equity: Common stock 0.3 0.3 Additional paid-in capital 115.2 114.2 Retained earnings 414.4 383.7 Treasury stock at cost (20.2) (15.9) Total Stockholders’ Equity 509.7 482.3 Total Liabilities and Stockholders’ Equity $ 781.0 $ 747.9 (1) Amounts are not restated and represent the amounts recognized under generally accepted accounting principles in place during that period.

35 Connection Proprietary & Confidential. Not for publication or redistribution © 2018 Connection All Rights Reserved. PC Connection, Inc. & SubsidiariesOther Key Operating Metrics / Stock Repurchases CONSOLIDATED SELECTED FINANCIAL INFORMATION UNDER PREVIOUS REVENUE RECOGNITION STANDARD 2018 2017 As Presented Impact of NewRevenue Standard Previous Revenue Standard Inventory turns 26 5 31 22 Days sales outstanding 53 (6) 47 47 Held in Treasury Shares Dollars Avg Price December 31, 2017 1,856,107 $ 15,862,317 $ 8.55 Q1 2018 Purchases 116,241 $ 2,997,217 $ 25.78 March 31, 2018 1,972,348 $ 18,859,534 $ 9.56 Q2 2018 Purchases 53,221 $ 1,386,556 $ 26.05 Total Treasury Purchases as of June, 30, 2018 2,025,569 $ 20,246,090 $ 10.00

PC Connection (CNXN) 8-KInvestor PresentationSidoti & Company Fall 2018 ConferenceSeptember 27th, 2018