Dec 7 (Reuters) - The Nasdaq extended a rally to hit a record high on Monday on growing hopes for the passage of a new stimulus bill, while the S&P 500 and the Dow dipped on Sino-U.S. tensions over Hong Kong. At 9:34 a.m. ET, the Dow Jones Industrial Average was down 67.35 points, or 0.22%, at 30,150.91, the S&P 500 was down 6.65 points, or 0.18%, at 3,692.47, and the Nasdaq Composite was up 23.40 points, or 0.19%, at 12,487.63. (Reporting by Shriya Ramakrishnan and Shreyashi Sanyal in Bengaluru; Editing by Shounak Dasgupta)