This monograph asks how the European sustainability reporting architecture—centered on the CSRD/ESRS and recalibrated by the Omnibus simplification package—reconfigures accountability from the single firm (micro) to the supply chain (meso). Likewise, it considered the institutional and data mechanisms through which this accountability can be made proportionate, comparable, and decision-useful. The analysis proceeded across the literature reviewed in the book and is anchored in the theoretical framework developed in Chap. 5 , which integrates (i) the sustainability of the value chain, (ii) the accountability of the value chain, and (iii) the intervening role of the institutional level (EFRAG/ESRS) into a single meso-level lens (Fig. 5.1 in Chap. 5 ). The framework clarifies how disclosure standards and transparency obligations can translate into supply chain governance routines: how the “arrows” between sustainability practices, accountability processes, and institutional levers coordinate expectations and evidence along upstream and downstream tiers according to the several issues involved in those three macro-dimensions.