SUGAR
March raw sugar was down 0.33 cent or 2.2 percent at 14.98 cents a lb by 1121 GMT, after touching a session low of 14.85 cents.
On Wednesday, prices rose to 15.37 cents, their highest since Nov. 28. The market has recently rallied on expectations that index funds will buy about 60,000 lots to rebalance their investments after sugar's poor performance in 2017.
However, prices retreated before Wednesday's close, which undermined the technical structure and discouraged further speculative buying, dealers said.
Dealers also noted the market had moved into overbought territory and its failure to once again break above highs had sapped momentum.
"Futures have failed to break the upper trend channel in recent months," said Geordie Wilkes, technical analyst at Sucden Financial, noting failure to hold above the 40-day moving average could pave the way for lower prices.
Dealers also said index funds may have already bought a large chunk of the volume they are targeting, leaving little room for further gains.
Fundamentally, focus also remained on ample global supplies, after analyst Green Pool on Wednesday boosted its surplus expectations for the 2017/18 season.
March white sugar was down $8.40, or 2.1 percent, at $390.90 a tonne.
COCOA
March London cocoa was down 28 pounds, or 2 percent, at 1,346 pounds a tonne, partly weighed down by a stronger British pound.
This extended losses from the prior session, with dealers noting that the market's failure to break through the 10-day moving average had weakened the technical structure and inspired chart-based selling.
Dealers also noted selling by producers looking to hedge their cocoa was adding pressure.
March New York cocoa also fell $38, or 2 percent, to $1,869 a tonne.
COFFEE
March arabica coffee was down 0.30 cents, or 0.2 percent, at $1.3065 per lb.
Prices earlier this week rallied sharply to their highest since Oct. 10, 2017 as speculators rushed to cover short positions.
March robusta coffee was unchanged at $1,735 a tonne.
The harvest in Vietnam's Central Highlands coffee belt was completed due to supportive weather, but low robusta prices in London have discouraged farmers from selling beans, traders said on Thursday.