The S&P 500 Healthcare sector (XLV) experienced a rise in average short interest during November, moving from 1.97% to 2.12%. Within this sector, Moderna (MRNA) remains the most heavily shorted stock.
The Health Care Select Sector SPDR® Fund ETF (XLV), representing the healthcare sector and holding a 12.12% weight in the S&P 500, has seen an 11.64% increase year-to-date, lagging the broader S&P 500 index (SP500) which rose 17.33% during the same period.
Stocks with the largest and least short positions
Ranked by short interest as a percentage of shares float
Seeking Alpha (Seeking Alpha) 
Moderna (MRNA) remained the most heavily shorted stock in the healthcare sector, with its short interest climbing to 19.01% of its float, up from 18.21% the previous month. Despite this high level of short selling, Seeking Alpha’s Quant Rating assigns the stock a “Hold” (score of 3.13/5). However, the company faces fundamental weaknesses, earning D+ grades for both profitability and growth, though it received a B+ for valuation.
Recently, Moderna chairman Noubar Afeyan cautioned that the U.S. is in “big danger” of lagging in vaccine technology research due to declining government investment and rising vaccine skepticism.
This bearish activity reflects underlying concerns: Seeking Alpha analyst Stephen Ayers pointed to the continued decline in COVID vaccine sales reported in the company’s recent Q3 report. The company’s heavy dependence on these sales, coupled with increased competition and diminishing demand, poses a significant threat to its near-term revenue growth and market performance.
Industry Analysis
Average short interest as a percentage of floating shares
Seeking Alpha (Seeking Alpha) 
The majority of sub-industries within the sector saw their short interest rise throughout November: For the twentieth consecutive month, the biotechnology industry held the distinction of being the most shorted in the healthcare sector, with short interest rising to 3.07% from 2.93% in November. The Life Sciences Tools and Services sector followed with a short interest of 2.30% at the end of November, up from 2.10% in the prior month.
In contrast, the pharmaceuticals industry recorded the lowest short interest among the healthcare sub-sectors in November, with a short percentage of 1.79% for the month, up from 1.63% in the prior month.
Related ETFs: Health Care Select Sector SPDR Fund (NYSEARCA:XLV), SPDR S&P Pharmaceuticals ETF (NYSEARCA:XPH), VanEck Pharmaceutical ETF (NASDAQ:PPH), iShares Nasdaq Biotechnology ETF (NASDAQ:IBB), iShares U.S. Pharmaceuticals ETF (NYSEARCA:IHE), and Invesco Nasdaq Biotechnology ETF (NASDAQ:IBBQ).