This paper investigates how buyers assess the importance of various attributes of supply chain sustainability disclosed by suppliers. These include different types of disclosure (i.e., product, process, and sourcing network), self- and third-party verified disclosure, partial and full disclosure, as well as the attributes associated with information disclosure using blockchain technology: immutability and update frequency. Building on concepts in signalling theory and inter-organisational trust, our research uses a choice-based conjoint experimental design to elicit responses from 234 managers with decision-making roles in procurement. Using this design, we calculate the relative importance of attributes, part-worth utility, and marginal willingness to pay, and test hypotheses about buyer preferences and willingness to pay. Our research reveals that buyers prefer suppliers with sustainability signals that span across different types of disclosure and methods of disclosure. It emphasises the importance of how sustainability information is disclosed, highlighting buyer trust in self-disclosure and a preference for comprehensive, regularly updated information. However, we find mixed results for buyers' willingness to pay. For instance, buyers prefer third-party verified supply chain transparency, but we do not find a significantly higher willingness to pay for such information compared to self-disclosure. The implications suggest a competitive advantage for suppliers adopting voluntary disclosure, prioritising disclosure based on buyer preferences, and recognising the limited direct impact of blockchain technology. Our research contributes to advancing our understanding of information disclosure in supply chain transparency and presents new avenues of inquiry into the value of blockchain-enabled platforms in supply chain sustainability reporting.