运营者术语表

Open exchange（公开竞价库存 / 公开交易市场）

Open exchange 是面向所有合格买家实时竞价的公开库存池，价格随市场需求浮动而非提前谈定，是 Amazon DSP 里最便宜、也最不可控的一层供给。

Amazon 的划分很干净：open auction 走 variable CPM，随市场需求浮动；deal 走 fixed CPM，而 deal 又分两种——PMP 是提前谈好的 floor CPM，本质仍然是竞价，programmatic guaranteed 才完全不参与竞价。真正的坑在于：DSP 默认出价策略是「While spending full budget, maximize performance」，按 Amazon 的公开说明，预算交付排在表现之前；max average CPM 只是你可以手动设置的上限，Amazon 并未公开单次出价在它之下如何运作，也从未公开清算是一价还是二价（三方供给本来就由各家 exchange 定规则）。所以别脑补竞价引擎，去看报表：把 open exchange 拆成独立 ad group，配自己的 max average CPM，按 supply source 维度读数据，别看 ad group 平均值。

关键数字

费率与规则以官方英文原文为准，保留原文：

Amazon Ads' pricing-transparency guide states, in its Amazon Publisher Services section, that variable CPM prices apply to open auction bidding where CPMs fluctuate due to market demand, while fixed CPM prices apply to deals and are set based on a variety of supply/demand factors.
Amazon's published default Amazon DSP bid strategy is “While spending full budget, maximize performance,” which Amazon says gives first priority to budget delivery and second priority to campaign performance, and max average CPM is an optional limit advertisers apply manually, with Amazon not publishing how individual bids behave beneath it.
Amazon does not publish whether the open-exchange clearing price is first-price or second-price, and on third-party supply the auction is run by the exchange rather than by Amazon DSP.

官方来源：Amazon Ads — PMP advertising: a practical guide to private marketplaces · Amazon Ads — Your guide to Amazon Ads pricing transparency · Amazon Ads — Bid strategies for Amazon DSP self-service orders