This study examines the left-digit bias of individual and institutional investors using the microstructural data set from a highly liquid index futures market. Both investor groups exhibit excess buying after the ask falls with a tens-digit decrement, whereas excess selling (buying) is observed only for institutions (individuals) after the bid rises with a tens-digit increment. Such excess buying is generally pronounced when price uncertainty is high. Institutional excess selling is evident when uncertainty is low and immediately after the market opens. While both investor groups focus on cognitive reference points, our findings imply that investors heterogeneously respond to the bias and that individuals experience investment losses as they trade on the bias.

中文翻译：

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左位数字偏差：个人和机构投资者

本研究使用流动性高的股指期货市场的微观结构数据集检验了个人和机构投资者的左位数偏差。两个投资者群体在卖价下降数十位数字后都出现了超额买盘，而只有机构（个人）在买价上涨数十位数字后才出现超额卖盘（买盘）。当价格不确定性很高时，这种过度购买通常会很明显。当不确定性较低且开盘后立即出现机构性超额抛售时，机构的过度抛售就很明显。虽然两个投资者群体都关注认知参考点，但我们的研究结果表明，投资者对偏见的反应各不相同，并且个人在根据偏见进行交易时会遭受投资损失。