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Intraday Stealth Trading and Volatility: The Evidence from the Warsaw Stock Exchange

The intraday volatility and volume U-shape pattern is well documented in the literature. It describes the common pattern of investor’s behavior on the stock markets: investors trade in the beginning and the end of the day more intensive than in the lunch time. However that pattern does not differentiate between trades’ sizes and investors characteristics. The stealth trading hypothesis states that informed traders tend to hide their information. There is a need for such behavior at the time of low volatility and they may achieve this by breaking up their trades into smaller parts. At the time of high volatility informed traders are willing to place large orders at the beginning and the end of the trading day because high volatility provides a sufficient camouflage for their information. We examine volatility pattern for small, medium and large trades and consider how durations between trades and spreads differ between trade size categories. Our sample consists of the data from the Warsaw Stock Exchange, which is organized as an order driven market. We show that medium-size trades are associated with relative large cumulative stock price changes, however these results are not robust when liquidity measures and durations between the consecutive trades are taken into account.