运营者术语表

第二价格竞价（second-price auction / GSP）

赢家只需付到刚好压过下一名的价格，而不是自己出的价；亚马逊称其广告自 2006 年起就用这套 GSP 机制，但如今竞价结果和账单之间还隔着一层 reserve price，FTC 则指控这已实质变成 first-price auction（尚未裁决）。

排名和定价是两回事：排名看 bid 加相关性，亚马逊没公布权重，争议全在定价这一步。官方 auctions 帮助页（2026 年 4 月更新）已不再写 second price，只说你付的价可能高于第二名出价，但绝不会超过你自己设的 bid。2026 年 8 月 31 日 FTC 联合 22 个州起诉，指控一项未披露的 soft reserve price 加价；亚马逊全盘否认并公布了自己的数据，法院尚未裁决。报表里没有 reserve 这一行，能做的只有：挑一个稳定的词，关掉 dynamic bidding，把 bid 砍 15–20% 盯 CPC。CPC 跟着一起掉，既可能是你在填底价，也同样可能只是普通 GSP 换了下家——这是线索，不是结论。

关键数字

费率与规则以官方英文原文为准，保留原文：

Amazon's help article "Understand Amazon Ads auctions" (updated April 27, 2026) never uses the phrase "second price", saying only that reserve pricing may affect your cost and that the price charged may exceed the runner-up bid but never your authorized maximum.
In an August 31, 2026 suit (W.D. Wash.), the FTC and 22 state attorneys general allege that an undisclosed "soft reserve price" raised the share of Sponsored Products clicks charged at the advertiser's own bid from 30–40% in 2021 to roughly 80% in 2024.
Amazon's public rebuttal, issued the same day, says about 92% of selected Sponsored Products ads in 2024 were not the highest bid and that inflation-adjusted average CPC was flat from 2019 through 2024 — self-reported figures, untested in court.

官方来源：Amazon Ads Support Center - Understand Amazon Ads auctions (updated Apr 27, 2026) · FTC - FTC, States Sue Amazon Over Secret Ad Surcharge Scheme (Aug 31, 2026) · FTC - Complaint, FTC et al. v. Amazon.com (W.D. Wash., Aug 31, 2026)