London coffee futures tumbled to a 21-month low on Thursday in the most active trading session in about a month, sparking market talk that a large investor is shedding its long position.
Liffe benchmark September contract settled $36, or 5.5 percent weaker, at $619 a tonne, off a low of $610 and at a level not seen since October 2002.
"There's one big fund jacking it in," a trader said.
"Roasters aren't in the market because they're well covered and origin aren't selling at these low levels," he added.
The spate of sales was prompted when the September contract broke through a support level marked by analysts at between $664 and $655, dealers and analysts said.
The September contract had its busiest day since June 30, with volume surging to 10,513 lots out of a total turnover of 26,528.