* December cotton closes above 100-day moving average

* Trading volumes light ahead of U.S. Independence Day holiday

* Thomson Reuters-Jefferies CRB index hits two-week high

NEW YORK, July 3 (Reuters) - ICE cotton gained on Wednesday in light trading, recovering the previous session's losses on renewed fund buying.

The most-active December cotton contract on ICE Futures U.S. closed up 1.02 cent, or 1.2 percent, at 85.74 cents a lb.

Fund buying lifted cotton prices, as the entire Thomson Reuters-Jefferies CRB index, a benchmark for global commodities markets, climbed to the highest level in almost two weeks, on gains in energy and agricultural markets.

"We're seeing some buying after the end of the quarter loss; there's some funds coming back in," said a U.S. broker.

December fiber prices traded mixed throughout the week after falling about 4 percent last quarter, the weakest quarterly performance in a year.

Prices closed just above the 100-day moving average at 85.51 cents a lb.

Trading was light ahead of the U.S. Independence Day holiday on July 4, when the exchange will be closed. Cotton trading will resume with a delayed opening at 8 a.m. EDT (1200 GMT) on Friday.

Concerns over global economic health capped gains, as worries mounted over slowing growth in China, the world's leading consumer of many raw materials, and political and economic instability in Europe and the Middle East.

Exchange stocks fell for the first time in almost a month as dealers decertified about 25,000 bales, but they remained above 600,000 bales and near the highest levels since June 2010.

Weekly U.S. government export data is due on Friday, because of the U.S. holiday. (Reporting by Chris Prentice; Editing by Steve Orlofsky)