Vantage Principals

Stefan Haney

Managing Principal

Mat Philipsen


Calvin Freitas

Calvin Freitas


Stefan Haney

Managing Principal

Stefan Haney is a business and technology leader with over two decades of experience in e-commerce, software development, and supply chain. As a 15-year veteran of Amazon, with over 9 years at Accenture and internet startups, his experience includes building product, data, and engineering teams worldwide to drive innovation and business growth. Stefan is named in multiple patents for algorithms and processes built at after he joined in 2003. During his time at Amazon, his contributions scaled supply chain purchasing automation, drove massive growth of the Amazon Seller Marketplace business, and led the personalization of product display and purchase features in the Customer shopping experience worldwide.

Product Innovation across the Globe

Under his direction, Stefan’s teams launched dozens of customer-facing products including Seller Pricing tools, Selling Coach recommendations, and Seller Central small business management tools. Most recently, his teams integrated data science into e-commerce shopping features on Amazon product pages and drove shopping expansions into Saudi Arabia, UAE, India, Turkey, Brazil, and Australia. Stefan’s organization included Product Management, Software Engineering, Data Science, and Operations distributed across multiple locations worldwide.

As one of a few company-wide Customer Experience Bar Raisers, Stefan reviewed hundreds of proposed initiatives across the company against the Amazon Flywheel. In addition, he taught the Amazon writing and innovation processes in quarterly group trainings and one-on-one mentoring. He lived these processes as a contributor or owner of dozens of documents to Amazon senior leaders resulting in the launches of new Amazon business such as Amazon Seller Lending, Amazon B2B marketplace, and Amazon Handmade.

Stefan’s business ownership also included responsibilities for growing the Used products business on Amazon. During this period of ownership, Stefan launched a certified refurbished product program achieving over $1B of annual revenue in the first 12 months.

Technology Operations

Beyond product management, Stefan built and led the worldwide operations and availability for Amazon product shopping pages through high-traffic events such as Prime Day along with test, release, and performance optimization for thousands of releases in a distributed services environment. His teams continually pursued and set new standards in software performance optimization, latency, automation, and data security.

Hiring and Organizational Development

During his time at Amazon, Stefan conducted over 1300 phone and in-person behavioral interviews contributing to the employee growth of the Marketplace organization with 100s of new hires. He served as an Amazon Bar Raiser and trained others on Amazon hiring practices and team development during rapid organizational growth.

Amazon positions

Between December 2016 to August 2019, Stefan held the title of Director – Consumer Shopping Experience. Previously, Stefan held the position of Director – Seller Strategy and WW Sales Technology, while working at, Inc.. Stefan held this role for 21 months (March 2015 – December 2016). Before this, Stefan held the position of Director – Seller Experience, while working at, Inc.. Stefan occupied this position for 4 years (December 2010 – March 2015). Previously, Stefan held the position of Senior Manager Global Seller Tools, while working at, Inc.. Stefan held this role for 17 months (March 2009 – August 2010). Before this, Stefan held the position of Global Buying Systems Manager, while working at, Inc.. Stefan occupied this position for 5 years (November 2003 – March 2009).

Experience 2003-2019

Joined Amazon in 2003 and grew with the company while working in 3 areas—Supply chain, Marketplace, and Shopping platforms/Category verticals. Over 16 years, I interviewed more than 1000 people to expand and build dozens of new teams. I was privileged to learn strategic and innovation thinking behind Prime, AWS, and Kindle by attending and presenting in dozens of meetings with Jeff Bezos and S-team members. The teams I built then launched new products and software, generating over $30B of incremental revenue, and scaled across user volume in 19 traffic peaks for Holiday shopping and annual Prime Day.

Director, Buying Experience – Core Shopping Technology

Owner of Amazon’s product pages and associated technology. Led strategy, planning, development, and operations across data science, engineering, testing, and product management in Seattle and Bangalore to build customer shopping experiences and drive shopping innovation, product data API/platform. Responsible for user interface framework, and site-wide accessibility across desktop, mobile, tablet, and apps worldwide. Transformed the group into a data driven customer focused organization.

  • Rebuilt the organization’s leadership with promotions and over 40 new hires (including a site leader and senior tech leaders in Bangalore, and principal and senior principal engineers), and a new team of data scientists, data engineers, and analysts.
  • Drove over $2.5B of incremental sales revenue in 2019 through new customer features including dynamic image sizing, live video, product variations, mobile layouts, along with expanding machine learning applications, and algorithm optimization.
  • Reduced technical complexity, infrastructure costs, and improved operational efficiencies, by introducing hardened APIs for federated custom development, standardizing development policies, and accelerating deprecation of legacy architectures. Evangelized the new APIs to over 400 internal Amazon teams and supported over 10,000 deployments per year.

Director, Marketplace – Seller Strategy and WW Sales Technology

Drove third-party retail seller acquisition and marketplace dynamics prediction on Amazon, and defined strategy for seller/product acquisition targeting, seller CRM tools, and statistical analysis of programs driving seller growth.

  • Re-implemented Salesforce across 40 business units in 18 countries worldwide with no business disruption or negative team impact, products sold per lead and data security improved, resulting in a case study presented at Dreamforce in 2016.
  • Invented and delivered a recommendation system used to source promotional deals from vendors and sellers in support of the second annual Prime Day. The system was extended to drive increased volume and sell through everyday deals.
  • Architected and developed distributed systems for monitoring price and selection of competitors to close gaps between Amazon and competitor marketplaces including Wish,, AliExpress, Walmart, Rakuten, and Mercado Libre.

Director, Marketplace – Seller Tools

Built and managed 14 teams to deliver automated account management and merchandising tools for Amazon sellers, and statistical analysis of programs driving seller growth. Built organizational operating mechanisms including goal tracking, resource allocation across Marketplace as the organization grew from 74 to over 3500 personnel and expanded to 40+ business programs.

  • Led strategy for online tools ( included in the Marketplace annual plan presented to Jeff Bezos.
  • Owned and achieved 11 company “S-team” goals, contributing to Marketplace growth from $9B to over $100B in 8 years.
  • Proposed and created Amazon Selling Coach, delivering automated, personalized business recommendations to sellers across numerous marketing channels and user interfaces. Built the program from the ground up to over $1B in incremental revenue in 21 months by leveraging machine learning, AWS, and mobile app features.
  • Built a suite of digital products and services for Amazon sellers, including automated pricing capabilities, brand management, business reports, and personalized dashboards. The suite drove 800 bps improvement in price competitiveness and established parity between Amazon vendors and Sellers in merchandising offerings such as Enhanced Brand Content (A+) or Lightning Deals.
  • Accelerated growth in the Amazon used business by launching the certified refurbished program and revising the offer listing page with layout and policy changes generating $0.6B in incremental sales.

Additional Amazon Experience 

  • Amazon – Sr. Manager, Retail Systems: Scaled inventory management and purchasing tools from 4 to over 40 categories.
  • Amazon – Business Analyst, Supply Chain: Improved customer experience by driving “not in stock” promise accuracy to >98%.
  • Independent – Supply Chain Consultant: Implemented and improved supply chain systems for clients including Kraft and Bic.
  • Accenture – Consultant: Provided process, systems, and supply chain consulting for clients including Harley Davidson, Caterpillar, Bahlsen, and Microsoft.

Education and Additional Interests

  • Western Michigan University – Haworth College of Business, Lee Honors College – Bachelor of Business Administration with concentrations in Marketing and German
  • Active teacher of Amazon best practices, including Writing Like an Amazonian, CX Innovation, Hiring and Interviewing
  • Education advocate, active homeschooler, volunteer leader in youth choral music education, rugby & Little League baseball

Contact Stefan

[email protected] | 773-398-5344 | LinkedIn

Mat Philipsen


Mat Philipsen is a business and technology leader who likes to bring order out of chaos —whether leading teams at Amazon or as a Captain in the US Army. Mat led international product, program, and technology teams at Amazon for 7 years. Prior to that, he worked for 13 years in software and consulting startups that went on to be purchased by IBM and Xerox. Mat has a Bachelors and Masters in Business Administration with a technology focus from the University of Washington.

Contact Mat


Calvin Freitas

Principal Front-End Engineer

Calvin is a Principal Front-End Engineer and engineering leader who enjoys building websites and web applications. Calvin has built websites professionally since 2008 and mobile-optimized sites since 2011. He leverages a variety of technologies including JavaScript, TypeScript, Node.js, React.js, and CSS – with cloud and serverless technologies – to build and deliver world-class user experiences for e-commerce applications, B2B portals, dashboards, and internal tooling.

Over the past decade, Calvin spent 9 years at Amazon building high-performance websites including the Amazon UI framework (used by and the Amazon app), the Amazon product detail page, and Amazon’s Seller Central marketplace website (B2B portal). Since leaving Amazon, Calvin has worked on projects for companies including Microsoft, eMag, and Emsi.

Amazon Experience

During Calvin’s time at Amazon, he became one of the best-known faces in the web development community through his work on the Amazon UI framework, his front-end engineering leadership in Amazon’s retail and marketplace organizations, and through his drive to create the Front-End Engineer role. As a hiring Bar Raiser, he set the standard for how to interview front-end engineers. Calvin presented about technical and career topics at 10 internal Amazon WebDevCon conferences.

Education and Additional Interests

Calvin holds a Bachelors in International Studies from the University of Nebraska. He and his wife enjoy small-town living in the Pacific Northwest.

Contact Calvin