The price of US natural gas spiked sharply this week, after American energy agencies forecast household spending on heating will rise 15% this year to combat a colder winter. The predictions set off a swarm of speculators anxious for a profit and sent hedgers scrambling to cover their exposure.

On Tuesday, the price of natural gas contracts traded on CME Group's Nymex jumped 4.78% in a matter of hours. Prices for the benchmark Henry Hub natural gas futures for delivery next month rose to an intraday high of $3.51 per million British thermal units in early afternoon trading, from a midday low of $3.35.