PARIS (Reuters) - An activist investment fund wants French media group Vivendi to sweeten the planned spinoff of Universal Music Group with an extra cash dividend that would be more advantageous to minority shareholders. Vivendi, controlled by French tycoon Vincent Bollore, is planning to cash in on its crown jewel - the world’s biggest music label, which it has valued at 33 billion euros ($40.43 billion) - as streaming revenues fuel growth. In a transaction involving an Amsterdam listing, Vivendi aims to distribute 60% of Universal’s capital in kind to existing shareholders, which will allow Bollore retain a strong grip on the group. In a letter to Vivendi Chief Executive Arnaud de Puyfontaine, Bluebell Capital Partners, which did not disclose the size of its Vivendi stake, called on Vivendi to add a cash dividend of 3 billion euros to the deal. Bluebell, which rose to prominence with a campaign earlier this year to oust the boss of French yoghurt maker Danone, said the distribution-in-kind structure penalised investors, according to the letter seen by Reuters. “We view the particular structure proposed to (the annual shareholder meeting) as highly tax inefficient and respectfully question the steps already undertaken which in practice prevent more tax effective solutions,” partners Marco Taricco and Giuseppe Bivona wrote in the letter, dated May 21. They also called for Universal’s listing to be shifted to the New York Stock Exchange. Vivendi confirmed it received the letter, and a spokesman said the group would have dialogue with shareholders on June 22, at its annual meeting. Vivendi said earlier in May it could sell an additional 10% of Universal to an American investor as part of the deal. Universal, behind singers such as Lady Gaga and Taylor Swift, is currently 20% owned by a consortium led by Chinese giant Tencent. The remaining 80% is owned by Vivendi. Reporting by Sarah White, Gwenaelle Barzic; Editing by Cynthia Osterman Our Standards: The Thomson Reuters Trust Principles.