About
Sustainability is a complex topic. My goal is to make sustainability and ESG reporting simple and accessible to businesses of all sizes, whether large, medium or small.
To me, sustainability reporting should not be just a ticking the box exercise. When done well, it helps companies to obtain valuable insights on their business and to credibly communicate their sustainability performance.
Having several years of audit and accounting advisory services background helped me to gain deep understanding of internal processes and controls, as well as the data needed for successful sustainability reporting. I also gained expertise in the practical application of various reporting standards and their technical language to real life situations.
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Jannik Hassel
Wirtschaftsprüfer (German CPA) & Sustainability Reporting Specialist
Jannik is a certified German Wirtschaftsprüfer (CPA) and founder of justReporting, a registered audit firm specializing in sustainability reporting and assurance for mid-sized companies. Many SMEs are not directly subject to the CSRD but face growing ESG data requests from OEMs and large customers through the value chain. Jannik helps these companies navigate the full journey: Gap analysis and double materiality assessments VSME and CSRD/ESRS implementation Independent report assurance under ISAE 3000 Green electricity verification and supply chain assurance for international automotive OEMs With 10+ years of Big Four experience (EY, PwC, Deloitte), university lectureships in Business Analytics and sustainability reporting, and a seat on the IDW Digital Advisory Committee, he combines regulatory depth with a practical, technology-driven approach. Advisory and assurance from a single source.
justReportingFirm
Registered German audit firm (Wirtschaftspruefungsgesellschaft) specializing in sustainability reporting and assurance for mid-sized companies. justReporting supports SMEs navigating CSRD/ESRS requirements, VSME implementation, and value chain compliance — from gap analysis and double materiality assessments through to independent report assurance under ISAE 3000. The firm also provides green electricity verification and supply chain assurance for international automotive OEMs. Founded by Jannik Hassel (10+ years Big Four experience), justReporting combines regulatory depth with a practical, technology-driven approach.
Alejandro Guldris
ESG & Sustainability Specialist
Expert in ESG reporting frameworks including CDP, CSRD, EU Taxonomy, and SBTi validation. Specialized focus on GHG emissions calculation and reduction strategies, with project and proposal management experience.