The Critical Impact of Firms’ Market Value on Investor Behavior Following Pharmaceutical IPOs

This chapter analyzes stock return behavior following initial public offering (IPO) events in the pharmaceutical sector and examines factors that could have an impact on this behavior.The results of the research indicate a positive Cumulative Average Abnormal Return (CAAR) of 3.03% in the 20 days following the IPO until the end of the quiet period for all firms under examination, and a decline of tens of percent in the 18 months post-IPO. When the sample is divided into two subsamples according to firm size, a market value (MV) of US$500 million can be identified as a threshold for positive or negative post-IPO yields. Companies with an MV below this threshold experience a positive but not significant CAAR in the first 20 days post-IPO and a significant negative CAAR from day 31 onwards. In contrast, companies above this US$500 million threshold show a significant positive CAAR 20 days post-IPO, followed by a consistent increase in CAAR for the next few months. The results also indicate that MV, IPO proceeds, shareholder dilution and clinical phases are critical factors determining post-IPO returns. In conclusion, we suggest that investors recognize a US$500 million market value of a firm as a confidence threshold when investing in newly issued pharmaceutical companies. We postulate that firms valued above this amount attract more attention and gain greater investor confidence than do firms below this threshold. Lower-valued firms shares can be considered “lottery stocks,” as their IPO ignites a period of enthusiasm until the quiet period ends, where after investors’ attention to such firms gradually diminishes, and their focus moves on to their next potential lottery-like opportunity.