Aluminum prices must fall further to force production cuts outside of China after output from the world’s biggest producer rose to record levels and exports surged, according to Goldman Sachs Group.

A decline in prices this year won’t be enough to balance the global market and China “cannot be relied on” to restrain output, Goldman analysts led by Max Layton wrote in a May 17 note. China’s aluminum output rose to a record 2.59 million tons in April, according to the National Bureau of Statistics.

“We believe that prices will need to remain low and fall further during 2015 in order to induce further ex-China closures so as to balance the market,” Goldman wrote. The bank is forecasting a slight surplus this year and an average price of $1,800 a metric ton for delivery in three months on the London Metal Exchange.

Global smelters will consider production cuts when prices, including regional premiums, fall below $1,875, Goldman said. The current “all-in” price is at about $1,980 in Europe, down 23 percent over the past six months, and $2,120 in the U.S. Midwest, down 18 percent, the bank said.

The global aluminum industry is coping with a surge of Chinese aluminum shipments driven by relatively higher prices outside the country, and a 13 percent tax rebate it allows on some exports.

China may export about 5 million tons of aluminum this year, eliminating a deficit, Vladislav Soloviev, chief executive officer of the world’s biggest aluminum producer United Co. Rusal Plc, said on May 13.

“Despite China’s high-cost aluminum producers losing money for the past two years, we find that their production has not been declining,” Goldman wrote.

Prices could fall below the bank’s $1,800 forecast if China’s domestic demand falls short and supply is not cut outside China, the bank said.

China’s aluminum exports grew 40 percent from a year earlier to 1.65 million tons in the first four months of 2015, according to customs.