This study looks at all companies registered in Northern Ireland and where their total assets are more than £800,000. The aim of this study is to provide an overview of the key movers and shakers in the Northern Ireland corporate sector. Only key data has been isolated, particularly the company's net worth and total assets, but also their full name, date incorporated, registered office, activities, shareholders, directors (with date of birth, occupation and nationality) and number of employees. Two indicators of size are used: net worth and total assets. These are preferable to turnover which is influenced by profit margins and whether the companies are capital or labour intensive. A short summary of the corporate sector in Northern Ireland: There are some 120,000 small and medium-sized enterprises (SME) accounting for 75% of the turnover and employment in the private sector. This SME sector provides 81% of private sector non-financial GVA or nearly half of the total GVA of Northern Ireland. The number of VAT/PAYE registered businesses rose by 1,560 (2.2%) to 71,615. This marks the third consecutive year of increase following a period of decline from 2008 to 2014. The largest increases in the number of businesses since 2016 were in construction (+355) and production (+260) whilst the only decreases were in wholesale (-60), retail (-10) and health (-5). The largest increases since 2009 have been in agriculture, forestry and fishing (+1,480 businesses or 9%); professional, scientific and technical (+760 businesses or 16%) and information and communication (+525 businesses or 39%). Both construction and retail have experienced large declines since 2009. Construction has experienced the largest decrease of all industries in terms of absolute number of businesses (-2,590). The retail industry remains 11% (760 businesses) smaller than in 2009. Of the 71,615 businesses, 2.3% were non-Northern Ireland owned. However, these businesses accounted for almost one quarter of Northern Ireland employees.