Short bets on S&P 500 Healthcare sector rises marginally to 1.91% in September; MRNA remains most shorted stock

[Health Care Medical Stock Market Industry Sector Wall Street Buildings 3d Illustration]
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The S&P 500 Healthcare sector (XLV) saw a slight increase in average short interest in September, rising to 1.91% from 1.89% the month prior. Moderna (MRNA) remains the most heavily shorted stock within this sector.

Despite its significant 12.12% weighting in the S&P 500, the healthcare sector has struggled to keep pace this year. The Health Care Select Sector SPDR Fund (XLV) returned only 3.30% year-to-date, compared to the S&P 500's 11.41% gain.

STOCKS WITH THE LARGEST AND LEAST SHORT POSITIONS

_Ranked by short interest as a percentage of shares float_

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Moderna (NASDAQ:MRNA [https://seekingalpha.com/symbol/MRNA]) continued its position as the most heavily shorted stock in the sector, with short interest climbing to 18.66% of its float, up from 17.42% last month. Despite the high short position, Seeking Alpha's Quant Rating gives the stock a "Hold" with a score of 2.90 out of 5.

In late September 2025, Moderna (NASDAQ:MRNA [https://seekingalpha.com/symbol/MRNA]) reported strong immune responses from its updated COVID shot [https://seekingalpha.com/news/4497661-moderna-updates-late-stage-trial-data-covid-shot]. However, the market is facing challenges due to a CDC advisory panel changing vaccine recommendations and lower demand.

The second- and third-most shorted stocks were DaVita (NYSE:DVA [https://seekingalpha.com/symbol/DVA]) at 9.62% and Henry Schein (NASDAQ:HSIC [https://seekingalpha.com/symbol/HSIC]) at 8.48%.

Conversely, major industry players like Johnson & Johnson (NYSE:JNJ [https://seekingalpha.com/symbol/JNJ]) (0.76%), Medtronic (NYSE:MDT [https://seekingalpha.com/symbol/MDT]) (0.83%), and Eli Lilly and Company (NYSE:LLY [https://seekingalpha.com/symbol/LLY]) (0.91%) saw minimal short interest in September.

INDUSTRY ANALYSIS

_Average short interest as a percentage of floating shares_

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Seeking Alpha (Seeking Alpha)
For the eighteenth consecutive month, the biotechnology industry held the distinction of being the most shorted in the healthcare sector, with short interest rising to 2.86% from 2.69% in August. Similarly, the healthcare provider and services sector saw its short interest rise to the second-highest level at 2.32%, up from 2.41% in the prior month.
In direct contrast, the pharmaceuticals' industry maintained the lowest level of short interest, which fell to 1.53% for the month.

RELATED ETFS: Health Care Select Sector SPDR Fund (NYSEARCA:XLV [https://seekingalpha.com/symbol/XLV]), SPDR S&P Pharmaceuticals ETF (NYSEARCA:XPH [https://seekingalpha.com/symbol/XPH]), VanEck Pharmaceutical ETF (NASDAQ:PPH [https://seekingalpha.com/symbol/PPH]), iShares Nasdaq Biotechnology ETF (NASDAQ:IBB [https://seekingalpha.com/symbol/IBB]), iShares U.S. Pharmaceuticals ETF (NYSEARCA:IHE [https://seekingalpha.com/symbol/IHE]), and Invesco Nasdaq Biotechnology ETF (NASDAQ:IBBQ [https://seekingalpha.com/symbol/IBBQ]).

MORE ON THE HEALTH CARE SELECT SECTOR SPDR® FUND ETF

* XLV: Market Overreaction Could Drive Double Digit Shareholder Yield [https://seekingalpha.com/article/4822422-xlv-market-overreaction-could-drive-double-digit-shareholder-yield]
* XLV Vs. IHE: Will Pharmaceuticals Outperform Healthcare? [https://seekingalpha.com/article/4817656-xlv-vs-ihe-will-pharmaceuticals-outperform-healthcare]
* XLV: Life Expectancy, Patents, And A Positive Outlook Will Pave The Way [https://seekingalpha.com/article/4801594-xlv-life-expectancy-patents-and-a-positive-outlook-will-pave-the-way]
* Notable healthcare headlines for the week: Novo Nordisk, Bristol Myers Squibb and J&J in focus [https://seekingalpha.com/news/4503400-notable-healthcare-headlines-for-the-week-novo-nordisk-bristol-myers-squibb-and-jj-in-focus]
* Generic drug imports unlikely to face tariffs - report [https://seekingalpha.com/news/4502853-generic-drug-imports-unlikely-to-face-tariffs]