MGM/UA said Ivan F. Boesky has a 5.7% interest.

In its recently filed 10K annual report to the Securities and Exchange Commission, the Culver City-based film studio said the New York-based investor disclosed his holdings Oct. 21 in a 13D filing to the SEC. Boesky is known as a risk arbitrageur, seeking short-term profits in stock investments, especially in firms that are considered likely to change hands. One entertainment industry analyst said Boesky’s investment in MGM/UA could be seen as another indicator that Turner Broadcasting System’s purchase of MGM/UA will be completed successfully.