The UK's trade body for EIS and SEIS - the Enterprise Investment Scheme and Seed Enterprise Investment Scheme. EISA is a highly effective not for profit organisation which exists to aid the provision of capital to UK small and medium-sized enterprises (SMEs) through the Enterprise Investment Scheme (EIS) and the Seed Enterprise Investment Scheme (SEIS). EISA works closely with HM Treasury, HM Revenue and Customs, Government Ministers, MPs and the FCA to enhance the EIS and promote the benefits of the scheme to investors and companies using EIS/SEIS and their respective advisers.