Copper prices slipped to their lowest in three-and-a-half months on Wednesday, hurt by rising inventory and selling by commodity trading funds.

Three-month copper on the London Metal Exchange (LME) was up 0.3% at $9,142 per metric ton during official rings, after dipping to $9,105 per metric ton to its lowest since April 3.

Computer-driven funds, known as managed futures or commodity trading advisors (CTAs), continued selling copper and pressuring prices, said Robert Montefusco, a commodities broker at Sucden Financial.

"Continued copper inflows to LME was also surprising," he added.

Copper inventory in warehouses monitored by LME rose to a 34-week high of 236,700 tonnes, exchange data showed. It has soared 28% since the start of July.

Rising copper stocks typically signal a weak consumption appetite.

Base metals sentiment will be guided by macro factors this week, Montefusco said, with the U.S. GDP data and personal consumption expenditure (PCE) price index data due later this week to shed light on when rate cuts might begin.

A lower interest rate pressures the U.S. dollar, making the greenback-priced metals cheaper for holders of foreign currencies.

Among other metals, aluminium was up 0.8% at $2,312.5, lead rose 0.4% to $2,068, nickel lost 0.4% to $15,950, zinc added 0.8% at $2,709.5 and tin jumped 2.6% to $30,175.

(Reporting by Julian Luk in London; Editing by Sonia Cheema)