TOKYO, Dec 1 (Reuters) - Japanese gas company Iwatani Corp on Friday said it will raise its stake in Cosmo Energy Holdings to 19.93% by buying shares from funds related to prominent activist shareholder Yoshiaki Murakami for 105.3 billion yen ($710.8 million).

Murakami's funds have raised their stake in Cosmo Energy to nearly 25% and have pursued a hostile takeover of the third-biggest Japanese oil refiner, ahead of a shareholder vote on Dec. 14. ($1 = 148.1400 yen) (Reporting by Kantaro Komiya; Editing by Edmund Klamann)