The firm invests in a diversified portfolio of quoted and unquoted securities of companies.Tata Investment Corporation on Friday said that its Board of Directors has approved a proposal to buyback 8.17 per cent of the total paid-up equity share capital of the company.According to a regulatory filing, the buyback will be for an aggregate amount not exceeding Rs 450 crore at Rs 1,000 per equity share."The buyback is subject to approval of the members by means of a special resolution through a postal ballot," the company said in a regulatory filing."The public announcement setting out the process, timelines and other requisite details will be released in due course in accordance with the buyback regulations."The firm invests in a diversified portfolio of quoted and unquoted securities of companies, including Tata Companies, which are engaged in various businesses.