BENGALURU, May 8 (Reuters) - Hindalco Industries , owned by Indian billionare Kumar Mangalam Birla, is considering seeking about $1.2 billion in the initial public offering of its U.S.-based unit, Novelis, Bloomberg News reported on Wednesday, citing people familiar with the matter. (Reporting by Manvi Pant in Bengaluru; Editing by Savio D'Souza)