互联网与文化michaeleisen.org
亚马逊那本标价 23,698,655.93 美元的苍蝇书
Amazon’s $23,698,655.93 book about flies
2011 — 2022，它一次次回到首页
黑点是上首页（≥ 50 分）的那次投稿，空心点是没冲上去的投稿，点越大分数越高。
导读
这篇博文讲的是亚马逊上一本关于果蝇的二手书被标到 23,698,655.93 美元。作者追查后发现，两家第三方卖家的自动定价程序互相参照——其中一家把价格设为另一家的约 1.27 倍，另一家又略低于对方——从而把价格推入不断抬升的失控螺旋。文章用一个荒诞案例揭示了自动定价算法在缺乏约束时会制造怎样的价格异常。
为什么经久不衰：它用一个具体、可复现的荒诞价格案例，清楚展示了自动定价与算法互动可能产生的系统性失控，至今仍是电商和算法交易领域的经典警示。
HN 评论精选
业内自动调价很普遍，但通常只覆盖重点商品并设置价格上下限。
我在一家中等规模的亚马逊第三方卖家工作。我们用自动调价；有成千上万个 SKU，不自动就没法保持竞争力。不过要考虑的层次很多，你绝不能把整个商品目录都交给自动调价。通常卖家只关注销量最好的前 X% SKU，其余让系统自动计算。我还纳闷我们有没有设置价格上限……补充：有的，我们有价格下限和上限。我都不知道自己刚才在想什么。
benvanderbeek查看英文原文
I work at a mid sized Amazon 3rd party seller. We reprice automatically. With thousands of SKU's there's no other way to be competitive. There are many layers to consider though, you definitely can't let your whole catalog auto-reprice. Usually sellers just focus on their top X% SKU's and let the rest auto-calculate. I wonder if we have a price ceiling setup...? Edit: Yes we have a floor and ceiling. I have no idea what I was thinking.
天价标价并非孤例，亚马逊上存在多本被推到数亿美元的书。
快速访问一下亚马逊：[链接] 有多本书标价超过 6 亿美元，其中一本还有 9.99 美元的 Kindle 版。
Qz查看英文原文
A quick visit to amazon: http://www.amazon.com/gp/search/ref=sr_adv_b/?search-alias=stripbooks&unfiltered=1&sort=-price Multiple books priced upwards of $600m. One has a Kindle edition for 9.99.
最合理的解释是平台支持的自动调价，而非洗钱等阴谋论。
奥卡姆剃刀：这是自动定价，不是洗钱，哈哈。亚马逊为此提供了接口，可以设定自动更新价格的规则；这在网上图书市场非常常见。[链接]
stagger87查看英文原文
Occam's razor. Automated pricing, not laundering, lol. Amazon provides an interface for it. Provide rules for automatically updating price. Very common in the online book market. https://sellercentral.amazon.com/help/hub/reference/external/G201994820?ref=efph_G201994820_cont_43381&locale=en-US
高价挂单可能是一种押注稀缺需求的类做市/套利策略，但应有价格限制。
我怀疑这种策略类似金融小市场里的“夹住价差”：同时挂略高于市价的卖单和略低于市价的买单，并随市场移动；偶尔大单扫过，买单或卖单成交后再补单。关键是总是略低于市价买、略高于市价卖，市场越波动越可能赚钱。把书标高价也类似：卖家赌某门课的学生会集中需要这本稀有书，便宜货被抢完后，总有人被迫买高价。也许该设限，但为了一本书不值得费劲。
shaftway查看英文原文
I suspect the strategy is similar to bracketing. Bracketing isn't uncommon in small financial markets. You basically put a sell order in at a price a bit higher than the market and a buy order in a bit cheaper than the market. As the market moves, you also move your orders. The thing is you can't move them perfectly in sync with the market, and occasionally a large order comes in that blows through a few orders in the deck. So when someone comes along and buys a big chunk your sell order gets exercised. Someone else comes along and sells a big chunk and your buy order gets exercised. As soon as the orders are exercised you replace them. The key is that you're always buying for a bit less than market, and always selling for a bit more than market. As the market moves you strongly tend to make money, regardless of which direction it goes. The more volatility, the more you are likely to make. I think the strategy for being the higher priced book is similar. The seller knows it's a rare good, and they're counting on some class somewhere requiring the book. A bunch of students will need it all at once, and the cheaper copies will get snapped up, forcing some students to buy it at the higher price, and boom, your sell order at just above market got executed. Maybe they should have limits, but it's just one book and it's unlikely to turn much of a profit, so it probably wasn't worth the effort.
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