1042 GMT - Copper markets are showing signs of tightening supply, with inventories increasingly concentrated in the U.S., high Chinese physical premiums and mounting mine supply challenges, according to Morgan Stanley. About 80% of global visible inventories are now held in the U.S., leaving markets elsewhere increasingly tight. Meanwhile, in China, smelter maintenance and reduced scrap availability are supporting demand for refined copper despite softer end-use consumption. Morgan Stanley expects copper to average $14,800 a metric ton in the fourth quarter and $14,400 in the first quarter of 2027. However, the bank says it is more cautious over next year's full outlook, citing uncertainty around U.S. tariff policy, an expected return to growth in mine supply and the likelihood that U.S. imports will eventually slow. LME three-month copper futures are up 0.9% to $14,251 a metric ton.