Personal data is an essential component of business models using the Internet of Things (IoT). Massive volumes of personal data are being recorded and analysed about consumers, despite them having limited understanding about how it affects them. Perceptions and preferences in this space influence how consumers choose to interact with the IoT, to a large extent. Yet little is understood about how industry perceives the views of consumers regarding the use of their personal data. To address this gap, we conducted three workshops with IoT industry stakeholders exploring their perspectives of consumer conceptions of the value of personal data in IoT. From the workshops, three overarching analytical themes emerged: (1) A perception of a significant gap between industry and consumers' understanding of what personal data is, who owns it, how it is used in IoT products and how it drives value in IoT businesses; (2) Perceived imbalances of power between industry and consumers in the control of and value extracted from personal data, with implications for inequalities between different consumer groups; and (3) A need for greater education and transparency for consumers, and for industry, about how personal data can be used. We develop a tentative five-point manifesto for the use of personal data in IoT, and conclude that a deeper understanding of consumer perspectives by industry would be positive for the ethical development of the IoT.