Rubber slumps as strength of dollar cuts appeal

TOKYO - Rubber slumped on concern that China may tighten trading rules to curb excessive speculation, and as a stronger dollar reduced the appeal of commodities as alternative assets.

The April-delivery contract declined on Wednesday as much as 1.4 percent to 335.7 yen a kilogram ($4,107 a ton) on the Tokyo Commodity Exchange before settling at 337 yen. Shanghai futures plunged on Wednesday as much as 4.4 percent to 31,210 yuan ($4,669) a ton after reaching a record 33,320 yuan on Tuesday.

Commodities in China snapped a rally as the Zhengzhou Commodity Exchange on Tuesday increased the margin requirement for rice, rapeseed oil, wheat and sugar trading to 8 percent from 3 percent or 4 percent.