Long-awaited rules to limit speculation in energy markets were revealed by US regulators yesterday that fell short of the crackdown feared by commodity traders.

After months of debate on how far to regulate commodity-market trading following a heated political outcry over a spike in oil prices in 2008, the Commodity Futures Trading Commission proposed putting firm caps, known as position limits, on the number of futures and options any trader can hold in US crude oil, gasoline, heating oil and natural gas.

But the new limits are generous enough to allow most of the trading to continue unaffected, bankers said. Bart Chilton, the commissioner most adamantly in favour of these limits, said the mooted rules “actually err on the high side”. He added: “The proposed limits will certainly be seen by some as higher than appropriate.”