China moved to clamp down on excessive speculation in commodities on Monday after weeks of frenzied trading boosted prices and ignited fears of another bubble in its domestic markets.
Activity on China's largest commodity exchanges has surged in recent days with turnover in key steel contracts exceeding the combined volume of the Shanghai and Shenzhen stock exchanges on one day last week.
Investors around the world have zeroed in on the latest trading binge as the prices of many commodities have risen sharply, with iron ore gaining almost a third in just two weeks. Cash has started to flow into raw materials in part because Chinese officials imposed curbs on equities trading last year.
"China's latest speculative spike has stunned global markets," said Tom Price, a Morgan Stanley analyst.
Shanghai steel futures have risen more than 50 per cent this year and more than a fifth this month. Iron ore traded on the Dalian Commodity Exchange hit its highest level since September 2014 last week.
The surge led the country's largest commodity trading venues — the Shanghai Futures Exchange, Dalian Commodity Exchange and Zhengzhou Commodities Exchange — to curb activity by lifting transaction costs, margins and daily trading limits on some contracts.
Pricing power for the world's most important raw materials has shifted east during a decade of economic growth that has transformed China into the largest importer of almost every major commodity. Almost half of the world's most active commodity derivatives are now traded on Chinese exchanges.
Analysts said the trigger for increased speculative interest in commodities was a credit surge engineered by Chinese policymakers this year to prop up the economy and its currency.
This led to a pick-up in construction activity and stoked investor appetite for ways to bet on the Chinese economy. Beijing imposed draconian rules on equities last year as fears of a slowing economy triggered a sell-off that threatened stability.
"The Chinese speculative community seems to have decided the big credit figures that came out two weeks ago were a green light to get levered up," Michael Coleman, co-founder of RCMA Asset Management in Singapore,
"They don't want to buy the stock market because of all the curbs that are in place and seem to have taken the view that commodities are really cheap."
Some traders are concerned higher trading costs could lead to a rapid unwinding of speculative positions and set off a new drop in commodities. Shanghai steel prices slipped 0.3 per cent on Monday, while iron ore futures also closed lower.
Analysts at OCBC Bank in Singapore said the recent rally was not entirely driven by speculation, with increased lending benefiting commodity-intensive industries. Still, the amount of trading in steel derivatives showed that speculative forces were a powerful influence on prices that investors had to watch.
"The risks for the correction of commodity prices cannot be ruled out," they said.
Exchanges in other parts of the world have also moved to raise transaction costs after a surge in prices and volumes. After soyabeans hit a nine-month high, the CME Group on Friday increased margins on its contracts.