The refinement and extension of the database were completed in four steps. First, the IoT Nation database, which was last updated by Data Mill North in August 2018, was downloaded from the website. The database contained 1344 companies registered in the UK and Ireland. The second step was to update entries in the database, by adding website addresses, phone numbers and the email addresses of companies. The database was extended by adding 203 companies from special IoT-related listings available on Crunchbase, Yell, Clutch, Good Firms and Beta Companies websites. That brought the total number of entries in the database to 1547. The third step was to review the updated database for the exclusion of foreign and non-IoT related companies (e.g. organisations providing government administrative functions, educational organisations etc). After applying the exclusion criteria, the database was reduced to 938 entries. The accuracy of address details, company registration numbers, company statuses and contact numbers was checked and links to companies? profiles were added by comparing them to Companies House information through a third panel resource. As a result of the removal of dissolved and non-active companies, the number of entries dropped to 872. At the fourth step, an additional 70 IoT-specific companies were added, making 942 companies in total. Missing information, such as the legal status, size, financial information and founding year was revised and appended programmatically using an external API. SIC codes were also imported using the Companies House API while SIC descriptions were imported using the Office of National Statistics listing.