上海期货交易所已暂停铜和铝期货的结算，交割来自保税仓库，这一机制长期以来帮助中国交易者避免为可在海外出售的金属缴纳税款。
The Shanghai Futures Exchange has suspended the settlement of copper and aluminum futures with deliveries from duty-free warehouses, a mechanism that has long helped Chinese traders avoid paying taxes on metal that can be sold overseas.
该机制于2010年引入，保税库存让上海交易者在海外价格有吸引力时，能够将金属卖往国际市场，并在进口划算时才通过中国海关并缴纳增值税。
Introduced in 2010, the bonded stockpiles give Shanghai traders the flexibility to sell their metal to international markets when overseas prices are attractive, and send it through Chinese customs and pay value-added taxes only when importing is worth the costs.
交易所周四宣布，即日起暂停铜和铝期货的保税交割业务。知情人士称，交易所向市场参与者通报，该决定是由于业务兴趣减弱，这两人要求不具名讨论非公开信息。交易所在正常营业时间外未立即回应置评请求。
The exchange on Thursday announced it would halt the bonded delivery business for copper and aluminum futures, effective immediately. The SHFE informed market participants that the decision was due to dwindling interest in the businesses, two people familiar with the matter said, asking not to be named discussing non-public information. The exchange didn’t immediately respond to a request for comment outside of regular business hours.
2018年出口窗口开放后，保税交割活动有所增加，但除此之外，这些仓单通常成本更高、流动性更差。
Activity with bonded deliveries picked up in 2018 when an export window opened up, but otherwise, those warrants are typically costlier and less liquid.
衡量中国进口需求的关键指标目前交投于历史高位附近。洋山溢价衡量中国进口商较伦敦金属交易所价格支付的溢价，周三已超过每吨200美元。
A key gauge of Chinese import demand is now trading near a record high. The Yangshan premium, which measures what Chinese importers pay above London Metal Exchange prices, surpassed $200 a ton on Wednesday.
一些分析人士认为，上海期货交易所的举措是一种预防性措施，旨在避免供应进一步紧张，因为中国铜库存低于一年中的典型水平。
Some analyst see SHFE’s move as a precautionary measure to avoid a further supply squeeze, as Chinese copper inventories are below typical levels for this time of year.
苏州创远合赢资本管理有限公司交易经理贾正在接受采访时表示，暂停保税交割可能有助于减缓中国金属外流，当上海与海外价格之间的套利激励此类交易时，此举可起到作用。
The suspension of bonded delivery could help slow outflows of metal from China when arbitrage between Shanghai and overseas prices motivate such a trade, Jia Zheng, a trading manager at Suzhou Chuangyuan Harmony-Win Capital Management Co., said in an interview.
贾正表示，影响应有限，上海期货交易所铜合约的保税交割很少，铝合约则相对较多。
The impact should be limited, with little bonded deliveries for SHFE copper contracts, and more for aluminum, Zheng said.