Plenty of research ( most recently, Cziraki et al. 2021) shows that insider buys contain value-relevant information while insider sales include little to no information. But what about the action of “not trading”?
The authors of this study ask the following:
Are the trades of portfolio insiders informative about the stocks they choose not to trade, those they choose not to buy, and those they choose not to sell?
What are the Academic Insights?
By studying SEC Form 3 and Form 4 filings provided by Thomson Reuters from 1992 to 2020, the authors find:
YES, but only those they choose not to sell. In fact, on average not-sold stocks earn large abnormal returns following a portfolio insider’s sale. This abnormal performance is long-lasting. A strategy that buys not-sold stocks following the required disclosure of portfolio insider sales earns significant alphas even after incorporating trading costs, and strategies that use longer holding periods are particularly successful after costs given their lower turnover and the long-term nature of the positive signals about not-sold stocks. For example, with an annual holding period, the not-sold portfolio earns a monthly CAPM alpha of 39 bps (annualized 4.7% alpha, statistically significant at the 5% level) and a monthly Carhart alpha of 37 bps (annualized 4.5% alpha, significant at the 1% level). The authors also show that the not-sold signal can complement other trading strategies like momentum. In fact, the research shows that buying not sold stocks that are also past winners earns particularly high alphas.
Why does it matter?
This study contributes to the academic work on stock returns following insider trades and to a growing literature studying insider inaction. Overall it suggests that traders can capitalize on the information about not sold stocks revealed by portfolio insider sales.
The Most Important Chart from the Paper:
Some individuals, e.g., those holding multiple directorships, are insiders at multiple firms. When they execute an insider trade at one firm, they may reveal information about the value of all—both the traded insider position and not-traded insider position(s)—the securities held in their “insider portfolio.” We find that insider “not-sold” stocks outperform “not-bought” stocks. Implementable trading strategies that buy not-sold stocks following the disclosure of a sale earn alphas up to 4.8% per year after trading costs. The results suggest that even insider sales that are motivated by liquidity and diversification needs can provide value-relevant information about insider holdings.
Dr. Elisabetta Basilico is a seasoned investment professional with an expertise in "turning academic insights into investment strategies." Research is her life's work and by combing her scientific grounding in quantitative investment management with a pragmatic approach to business challenges, she’s helped several institutional investors achieve stable returns from their global wealth portfolios. Her expertise spans from asset allocation to active quantitative investment strategies. Holder of the Charter Financial Analyst since 2007 and a PhD from the University of St. Gallen in Switzerland, she has experience in teaching and research at various international universities and co-author of articles published in peer-reviewed journals. She and co-author Tommi Johnsen published a book on research-backed investment ideas, titled Smarte(er) Investing. How Academic Insights Propel the Savvy Investor. You can find additional information at Academic Insights on Investing.
Performance figures contained herein are hypothetical, unaudited and prepared by Alpha Architect, LLC; hypothetical results are intended for illustrative purposes only. Past performance is not indicative of future results, which may vary. There is a risk of substantial loss associated with trading stocks, commodities, futures, options and other financial instruments. Full disclosures here.