The impact of fractional trading on risk aversion for non-professional investors

Abstract

We study the impact of fractional trading (FT) on non-professional investors' decision-making under uncertainty. Using the expected utility framework, we show that with the recent easiness to trade in stock markets and with the option to buy or sell a fraction of a share of a stock or ETF (exchange-traded fund), the risk appetite of non-professional investors might have gone up, increasing market participation and demand for stocks. Furthermore, we show that this change in the non-professional investor's risk aversion behavior varies by household income levels. Based on constructed probabilities, we estimate that approximately 83 billion dollars have been newly invested in stock market post-FT. Our results suggest that easy access to trade stocks and FT allows households with lower discretionary income a new tool to diversify their portfolio and participate in the stock markets by investing in different stocks and ETFs while at the same time having a significant impact on the stocks' price levels and price dynamics observed in the markets.