AI 中文总结
利用澳大利亚国家电力市场数据，研究共享算法对竞争的影响，通过估计电池储能动态价值等方法，发现共享算法致投标同步，特定份额下存在联合利润最大化行为，使消费者受损，且问题出在算法供应商层面。
AI 中文摘要
竞争公司越来越多地将定价和投标决策委托给同一第三方供应商提供的算法。我们利用澳大利亚国家电力市场的数据研究共享算法是否会导致竞争对手将彼此的利润内部化，在该市场中，每个电池的投标以5分钟频率被观察到，并且可以与可识别的自动投标供应商相关联。由同一供应商构建的投标会共同变动，并且在一项披露改革使共同稀缺状态更易于观察之后，这种共同变动更为强烈：引导电池进行有效套利的相同信息也使共享供应商的竞争对手的投标同步。为了将由于共享信息导致的共同变动与联合利润最大化区分开来，我们估计每个电池存储能量的动态价值，并在反事实投标下重新清算市场。所有者层面的利润无法解释观察到的投标行为：电池会放弃有利可图的调度，因为这会压低竞争对手公司拥有的同一供应商电池所获得的价格，并且对这些竞争对手利润的估计权重接近1。我们仅在供应商在接近边际的电池容量中所占份额超过约30%（对应于约20%的装机份额）的情况下发现这种行为的证据。已识别的这种行为使当前机队的消费者每年损失550万美元，并且它出现在算法供应商层面而非资产所有者层面，这是基于所有权的集中度筛选无法捕捉的一层。
英文摘要
Competing firms increasingly delegate market decisions to algorithms supplied by the same third-party providers. We study whether a shared algorithm leads competitors to internalise one another's profits, using data from the Australian National Electricity Market, where batteries' bids are observed at 5-minute frequency and can be linked to an autobidding provider. Bids constructed by the same provider co-move, and do so more strongly after a disclosure reform made the scarcity state easier to observe: the same information that steers batteries towards efficient arbitrage also synchronises the bids of competitors who share a provider. To separate co-movement from joint profit maximisation, we perform a conduct test by estimating each battery's dynamic value of stored energy and reclearing the market under counterfactual bids. We find that batteries forgo profitable dispatch in the evening peak when it would lower the profit of same-provider batteries owned by rival firms. The estimated conduct parameter is close to one. But this effect arises only where a provider's share of near-margin battery capacity exceeds roughly 30%. The identified conduct costs consumers an annualised $5.5 million given the battery fleet from 2025, and concentration analysis based on ownership would treat these batteries as independent competitors and miss the impact of shared autobidding software.
Comments76 pages. JEL codes: D43, D44, L41, L86, L94
