Abstract We investigate the determinants of insider trading and its effects on the levels of stock price informativeness in Brazil. We use corporate insider trading data for companies included in the IBrX-100 index between December 2016 and June 2018. In our standard sample, our findings indicate that insiders tend to trade in high liquidity months, and this behavior hampers the detection of adverse selection. Also, insider trading seems to be irrelevant to efficiency. Our study indicates that greater trading transparency is essential for outsiders to increase market efficiency since trading alone does not provide such a scenario. We suggest caution in the use of low-frequency liquidity measures for adverse selection detection in this market.

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关于巴西内幕交易：决定因素和信息影响

摘要我们研究了内幕交易的决定因素及其对巴西股票价格信息水平的影响。我们使用2016年12月至2018年6月之间包含在IBrX-100指数中的公司的公司内幕交易数据。在我们的标准样本中，我们的发现表明内幕交易者倾向于在高流动性月份进行交易，这种行为不利于逆向选择的发现。同样，内幕交易似乎与效率无关。我们的研究表明，提高交易透明度对于局外人提高市场效率至关重要，因为仅凭交易无法提供这种情况。我们建议在此市场中谨慎使用低频流动性衡量指标进行逆向选择检测。