CME Group的合约规格中提到TAS和TAM交易，如：
Gold Futures Contract Specs
Gold 期货 合约规格
Trading at Settlement (TAS) is allowed in the first ,second ,third and fourth nearby active contract months- February, April, June, August and December. TAS transactions may be executed at the current day’s settlement price or at any valid price increment up to 10 ticks higher or lower than the settlement price.
TAS trading terminates 3 business days prior to the contract month.
以结算价交易（TAS）可在有效合约月份进行。有效合约月份为2月、4月、6月、8月和12月。TAS交易可按当日结算价或高于或低于结算价十个最小波动单位的任何有效价格增幅进行。TAS交易在合约月之前3个营业日终止。
Trading at Marker (TAM) is analogous to our existing Trading at Settlement (TAS) wherein parties are permitted to trade at a differential that represents a not-yet-known price. TAM trading will use a marker price, whereas TAS trading uses the Exchange-determined settlement price for the applicable contract month. As with TAS trading,parties enter TAM orders at the TAM price or at a differential between one and ten ticks higher or lower than the TAM price. Trading at Marker is available for the London p.m. Marker on the nearest active month ( February, April, June, August, December).
以市价交易（TAM）易类似于我们现有的 TAS 交易，允许交易各方以未知的价差交易。TAM 交易将使用市场价格，而TAS 交易使用交易所为适用的合约月确定的结算价。如 TAS 交易一样，TAM交易各方将能够以TAM 价格或上下加减1至10个最小波动单位差价输入 TAM 交易单。
市价交易适用于伦敦下午时间最近的活跃月份（2月、4月、6月、8月、12月）。
英文摘自：https://www.cmegroup.com/trading/metals/precious/gold_contractSpecs_futures.html
中文摘自：https://www.cmegroup.com/cn-s/trading/metals/precious/gold_contract_specifications.html
那么什么是TAS呢？
Trading at Settlement (TAS)
TAS is an order type that allows you to execute at a spread to the settlement price at any time during the trading session. You can enter TAS order types up to 8 ticks above or below the settlement price, depending on the contract.
TAS是一种报单类型，允许你在交易阶段的任一时刻采用结算价或包含一定价差的结算价进行报单。
Key Benefits
Reduce uncertainty around the settlement price
Price contracts at or near the settlement value
Execute at any point of the trading day rather than waiting for the market close
Available on CME Globex and eligible for block trades
主要优势
降低围绕结算价的不确定性
合约采用结算价或结算价附近的价格
可以在交易日中的任何时间点执行，而不必等到收盘
CME Globex和大宗交易中可用
英文摘自：https://www.cmegroup.com/trading/trading-at-settlement.html
中文自翻，仅供参考