This study examines whether an increase in the transparency of investment transactions facilitates portfolio mimicking. While there are reported benefits of transparency in enhancing regulatory monitoring and discipline, an increase in the transparency of investment transactions can also facilitate mimicking of peer firms’ investment strategies. I exploit an exogenous increase in the broad dissemination of transaction-level investment disclosures of U.S.-based insurers and find a significant increase in portfolio similarity at the individual security level. Increases in portfolio similarity are more pronounced in smaller, less sophisticated insurers mimicking their larger, more sophisticated peers. Shared asset positions and common exposures to risk can exacerbate collective risk across firms. Accordingly, I find that the detectable increases in portfolio similarity are positively associated with measures of systemic risk, especially in those smaller insurers mimicking their peers. This study adds to a nascent literature on portfolio mimicking and highlights a potential negative externality of increased transparency.

中文翻译：

---

交易级透明度和投资组合模仿


本研究探讨了投资交易透明度的提高是否有利于投资组合模仿。据报道，透明度有利于加强监管监督和纪律，但投资交易透明度的提高也有利于模仿同行公司的投资策略。我利用美国保险公司交易级投资披露广泛传播的外生增长，发现个人安全级别的投资组合相似性显着增加。在规模较小、技术水平较低的保险公司模仿规模较大、技术较成熟的同行时，投资组合相似度的增加更为明显。共享资产头寸和共同面临的风险可能会加剧公司之间的集体风险。因此，我发现投资组合相似性的明显增加与系统性风险的衡量呈正相关，特别是在那些模仿同行的小型保险公司中。这项研究补充了有关投资组合模仿的新兴文献，并强调了透明度增加的潜在负外部性。