Benchmark Tokyo rubber futures ended down 4.8 percent on Wednesday, coming under pressure from Thailand's auction plan to ease supply worries following floods in key production areas. The benchmark Tokyo Commodity Exchange (TOCOM) futures extended declines to more than 10 percent in the past two days following a request by TOCOM to its member brokers to submit reports detailing their customers' positions on rubber after prices spiked to their highest since September 2011 on Tuesday.
TOCOM issued the notice on Monday and members are required to respond by Wednesday, a spokesman said.
The TOCOM rubber contract for July delivery finished 15.8 yen lower at 315.5 yen ($2.78) per kg, the lowest settlement since January 26.
The Shanghai market is closed due to lunar New Year holidays.
The front-month rubber contract on Singapore's SICOM exchange for March delivery last traded at 228 US cents per kg, down 2.2 cents.