DAY-OF-THE-WEEK EFFECT IN US BIOTECHNOLOGY STOCKS — DO POLICY CHANGES AND ECONOMIC CYCLES MATTER?
Abstract
This study examines the presence of the day-of-the-week effect on daily returns of biotechnology stocks over a 16-year period from January 2002 to December 2015. Using daily returns from the NASDAQ Biotechnology Index (NBI), we find that the stock returns were the lowest on Mondays, and compared to the Mondays the stock returns were significantly higher on Wednesdays, Thursdays, and Fridays. The day-of-the-week effect on returns of biotechnology stocks remained significant even after controlling for the Fama–French and Carhart factors. Moreover, the results from using the asymmetric generalized autoregressive conditional heteroskedastic (GARCH) processes reveal that momentum and small-firm effect were positively associated with the market risk-adjusted returns of the biotechnology stocks during this period. The findings of our study suggest that active portfolio managers need to consider the day of the week, momentum, and small-firm effect when making trading decisions for biotechnology stocks. Implications for portfolio managers, small investors, scholars, and policymakers are included.
References
- 1989] Seasonal and day-of-the-week effects in four emerging stock markets. Financial Review 24 (4), 541–550. Crossref, Google Scholar [
- 2015] The day-of-the-week effect is weak: Evidence from the European real estate sector. Journal of Economics and Finance 1–19. Google Scholar [
- 2001] The day of the week effect on stock market volatility. Journal of Economics and Finance 25 (2), 181–193. Crossref, Google Scholar [
- 1976] The pricing of commodity contracts. Journal of Financial Economics 3 (1), 167–179. Crossref, Google Scholar [
- 1987] A conditionally heteroskedastic time series model for speculative prices and rates of return. The Review of Economics and Statistics 69 (3), 542–547. Crossref, Google Scholar [
- 1992] ARCH modeling in finance: A review of the theory and empirical evidence. Journal of Econometrics 52 (1–2), 5–59. Crossref, Google Scholar [
- 2001] Leverage effect in financial markets: The retarded volatility model. Physical Review Letters 87 (22), 228701. Crossref, Google Scholar [
- 2000] The weekend effect, “reverse” weekend effect, and firm size. Journal of Business Finance & Accounting 27 (5–6), 555–574. Crossref, Google Scholar [
- 1997] On persistence in mutual fund performance. The Journal of Finance 52 (1), 57–82. Crossref, Google Scholar [
- 2007] Determinants of idiosyncratic volatility for biotech IPO firms. Financial Management 36 (4), 107–122. Google Scholar [
- 2003] The value spread. The Journal of Finance 58 (2), 609–642. Crossref, Google Scholar [
- 1973] The behavior of stock prices on Fridays and Mondays. Financial Analysts Journal 29 (6), 67–69. Crossref, Google Scholar [
- 1996] The day-of-the-week effect: The international evidence. Journal of Banking & Finance 20 (9), 1463–1484. Crossref, Google Scholar [
- Douglas, M (2014). Will obamacare harm these biotech stocks? Motleyfool.com. Available at: http://www.fool.com/investing/general/2014/03/15/will-obamacare-harm-these-biotech-stocks.aspx. Google Scholar
- 1986] The weekly pattern in stock index futures: A further note. The Journal of Finance 41 (5), 1149–1152. Crossref, Google Scholar [
- 1982] Autoregressive conditional heteroscedasticity with estimates of the variance of United kingdom inflation. Econometrica 50 (4), 987–1008. Crossref, Google Scholar [
- 2001] GARCH 101: The use of ARCH/GARCH models in applied econometrics. The Journal of Economic Perspectives 15 (4), 157–168. Crossref, Google Scholar [
- 2010] Follow-on biologics: A new play for big pharma: Healthcare 2010. The Yale Journal of Biology and Medicine 83 (2), 97. Google Scholar [
- 2002] The legacy of modern portfolio theory. The Journal of Investing 11 (3), 7–22. Crossref, Google Scholar [
- 1965] The behavior of stock-market prices. The Journal of Business 38 (1), 34–105. Crossref, Google Scholar [
- 1970] Efficient capital markets: A review of theory and empirical work. The Journal of Finance 25(2), 383–417. Crossref, Google Scholar [
- 2004] The capital asset pricing model: Theory and evidence. Journal of Economic Perspectives 18 (3), 25–46. Crossref, Google Scholar [
- 2006] The value premium and the CAPM. The Journal of Finance 61 (5), 2163–2185. Crossref, Google Scholar [
- 1980] Stock returns and the weekend effect. Journal of Financial Economics 8 (1), 55–69. Crossref, Google Scholar [
- 1981] Day of the week effects and asset returns. Journal of Business 54 (4), 579–596. Crossref, Google Scholar [
- 2013] Biopharmaceuticals under the patient protection and affordable care act: Determining the appropriate market and data exclusivity periods. Texas Intell. Prop. LJ 21, 213. Google Scholar [
- 1993] On the relation between the expected value and the volatility of the nominal excess return on stocks. Journal of Finance 48 (5), 1779–1801. Crossref, Google Scholar [
- 1985] The week-end effect in common stock returns: The international evidence. Journal of Finance 40 (2), 433–454. Crossref, Google Scholar [
- Kaufman, AC (June, 2015). Healthcare stocks soar after Obamacare victory in Supreme Court. Huffington Post (6/25/2015). Available at: http://www.huffingtonpost.com/2015/06/25/obamacare-stocks_n_7662752.html. Google Scholar
- 1982] Weekend effects on stock returns: A note. Journal of Finance 37 (3), 883–889. Crossref, Google Scholar [
- 2004] The adaptive markets hypothesis. The Journal of Portfolio Management 30 (5), 15–29. Crossref, Google Scholar [
- 1952] Portfolio selection. The Journal of Finance 7 (1), 77–91. Crossref, Google Scholar [
- 2014] Asymmetry and leverage in conditional volatility models. Econometrics 2 (3), 145–150. Crossref, Google Scholar [
- 2014] A one line derivation of EGARCH. Econometrics 2 (2), 92–97. Crossref, Google Scholar [
- 1991] Conditional heteroskedasticity in asset returns: A new approach. Econometrica 59 (2), 347–370. Crossref, Google Scholar [
- 2014] The changing healthcare landscape in the United States as a result of the passage of the Patient Protection and Affordable Care Act of 2010 and the Health Care and Education Reconciliation Act of 2010. International Journal of Pharmaceutical and Healthcare Marketing 8 (3). Crossref, Google Scholar [
- 1996] Evidence on weak form efficiency and day of the week effect in the Indian stock market. Finance India 10 (3), 605–616. Google Scholar [
- 2012] Day of the week effect in Latin American stock markets. Revista de Analisis Economico 27 (1), 71–89. Crossref, Google Scholar [
- 1964] Capital asset prices: A theory of market equilibrium under conditions of risk. The Journal of Finance 19 (3), 425–442. Crossref, Google Scholar [
- 1990] Day-of-the-week effect on the Paris Bourse. Journal of Banking & Finance 14 (2), 461–468. Crossref, Google Scholar [
- 2010] Drug development costs when financial risk is measured using the Fama–French three-factor model. Health Economics 19 (8), 1002–1005. Crossref, Google Scholar [
- 2011] Asymmetry in return reversals or asymmetry in volatilities? — New evidence from new markets. Quantitative Finance 11 (2), 271–285. Crossref, Google Scholar [