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April 6 (Reuters) - Goldman Sachs said on Monday it expects the global copper market to move into a larger surplus in 2026 and trimmed its price outlook, citing weaker demand growth linked to an energy-driven slowdown in the global economy.

The bank said it now expects a surplus of 490,000 tonnes of refined copper in 2026, up from a previous estimate of 380,000 tonnes, while cutting its average 2026 copper price forecast to $12,650 a tonne from $12,850.

Goldman lowered its global refined copper demand growth forecast for 2026 to 1.6% year-on-year from 2.0%, after its economists estimated that higher energy prices could shave 0.4 percentage points off global GDP growth.

It said copper demand remains more resilient than other metals, reflecting its increasingly strategic and structural role.

Keeping production assumptions unchanged, the weaker demand outlook leads to a larger inventory build, with the ex-U.S. market expected to be close to balance, prompting nearly a 2 percentage point downward revision to year-on-year copper price changes.

In the near term, Goldman expects copper prices to remain volatile as markets assess the impact of Middle East tensions on growth.

Assuming energy flows through the Strait of Hormuz begin to recover from mid-April and the U.S. Federal Reserve delivers two rate cuts later this year, the bank forecasts copper to average $12,700 in the second quarter of 2026 before easing toward a fair value of $12,000 by the second half.

Goldman said risks are skewed to the downside if disruptions to Hormuz flows persist, keeping energy prices elevated and weighing further on growth.

Beyond 2026–27, Goldman maintains its view that copper prices could rise to $15,000 by 2035 as supply constraints emerge and demand from electrification and grid investment accelerates.