HONG KONG, Nov 8 (Reuters) - Hong Kong shares suffered their worst day since July 23 on Thursday, as investors took profits on recent outperformers and turned their attention to the prospect of U.S. fiscal woes roiling financial markets.
The Hang Seng Index fell 2.4 percent to 21,566.9 points, reversing the benchmark's strong start to November. The China Enterprises Index of the top Chinese listings in Hong Kong sank 2.7 percent.
In the mainland, the CSI300 Index of the top Shanghai and Shenzhen listings suffered a fourth-straight loss, sliding 1.8 percent. The Shanghai Composite Index lost 1.6 percent. The falls were the worst since Oct. 26.
* Chinese oil majors came under pressure after oil prices dived 4 percent overnight on growing economic headwinds on both sides of the Atlantic coast. Petrochina Co Ltd and CNOOC Ltd each fell 3 percent, while China Petroleum & Chemical Corp (Sinopec) lost 1.7 percent.
* But the Chinese railway sector bucked broader market weakness after mainland news outlets reported that Beijing could raise its investment in the sector. China Railway Group rose 2.2 percent, while China Railway Construction gained 1 percent.
* Thursday's losses came as China formally started a once-in-a-decade political transition with the 18th Communist Party congress meeting in Beijing, where outgoing President Hu Jintao vowed reforms to make the currency and interest more market-based, boost overseas investments and plough more state funds into industry as part of plans to keep GDP on track to double in size by 2020.
* Beijing will post a fresh batch of economic data, starting with inflation, urban investment, industrial output and retail sales on Friday. Trade data is expected on Saturday, with money supply and loan growth at any time between Nov. 10 and Nov. 15.