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SYDNEY, June 20 (Reuters) - Australian shares dived 2.1 percent on Thursday, its largest one-day drop in four months, as global equities tumbled after Federal Reserve Chairman Ben Bernanke confirmed fears the U.S. central bank could begin to scale back its stimulus measures later this year.
Banks led the sell-off, with top lender the Commonwealth Bank of Australia down 3.1 percent. Westpac Banking Corp dropped 3.7 percent and National Australia Bank lost 2.8 percent.
Australian shares were further hit by the HSBC China flash Purchasing Managers' Index, which stood at 48.3 in June from May's final reading of 49.2. It drifted further away from the 50-point level demarcating expansion from contraction.
The reading has hit its weakest level since September as new orders faltered, reinforcing signs of tepid economic growth in the second quarter.
The S&P/ASX 200 index dived 103 points to finish at 4,758.4, according to the latest data. The benchmark rose 1 percent to close at a two-week high on Wednesday.
New Zealand's benchmark NZX 50 index lost 1.1 percent or 47 points to finish the session at 4,398.5. (Reporting by Thuy Ong; Editing by Jacqueline Wong)