By virtue of paragraph(s) 3 of Part 1 of Schedule 12A of the Local Government Act 1972.
Information relating to the financial or business affairs of any particular person (including the authority holding that information).
The public interest in maintaining the exemption outweighs the public interest in disclosing the information because it contains information relating to the financial or business affairs of the Council in terms of its investment portfolio and the financial management of the portfolio.