Biotech IR Blog by Our CEO and Founder, Laurence Watts.
July 15, 2026
Average Biotech Short Interest at 1H’26
Regular readers of this blog will know that we publish average biotech short interest every six months. It’s that time of year, so what follows is the average short interest among NBI constituent companies at 1H’26.
A reminder of where we obtain our short interest data:
While long positions are disclosed via 13F reports, knowing who has taken a short position in a company’s stock is more difficult to ascertain.
This is because the information we have on short positions comes not from funds, but from the brokers they utilize in running their portfolios. FINRA Rule 4560 mandates that every member (i.e., every broker) must report total short positions (both customer and proprietary accounts) in all equities, in both the middle of and at the end of each month. FINRA then provides the data to exchanges like Nasdaq and the NYSE for public disclosure. Importantly, because only the total short position is revealed, there is no way to know precisely which fund, broker or individual has actually shorted a stock.
We are publishing our 1H’26 blog now because the short information on Nasdaq-listed biotechs was made public on July 10, 2026 (approximately two weeks after mid-year).
Methodology
Once again, we examined short interest across “small,” “medium” and “large” Nasdaq-listed biotechs.
- We took the 251 constituents of the Nasdaq Biotechnology Index (NBI) as of June 30.
- Since the floor for NBI inclusion is a $200 million market cap, we excluded biotechs with lower market caps from our analysis.
- At the other end of the spectrum, we decided to exclude any biotech with a market cap of more than $10 billion.
- This left us with 77 “small” biotechs, 66 “medium” biotechs, and 57 “large” biotechs, as shown in the table below.
| Description | Market Cap Range | Number of Biotechs |
| < $200M | < $200M | 14 |
| Small Biotechs | $200M – $1B | 77 |
| Medium Biotechs | $1B – $2.5B | 66 |
| Large Biotechs | $2.5 – $10B | 57 |
| > $10B | > $10B | 37 |
Source: Nasdaq, New Street Investor Relations
Once again, the primary metric we analyzed was Days to Cover. Days to Cover is the best metric for assessing short positions because it blends short interest with liquidity. Instead of just showing how many shares are shorted, it shows how hard it would be for shorts to exit, by dividing the absolute short interest by a stock’s average daily trading volume. High Days to Cover signals a crowded trade and a greater squeeze risk.
Average 1H’26 Biotechnology Short Interests:
“Small” Biotechs ($200M-$1B), n=77
| Date | December 31, 2024 | June 30, 2025 | December 31, 2025 | June 30, 2026 |
| Average Short Interest (Days to Cover) | 8.0 | 8.1 | 7.5 | 6.3 |
Source: Nasdaq, New Street Investor Relations
- At 1H’26, the average (mean) short interest in a “small” biotech was 6.3 Days to Cover, down from 7.5 Days to Cover at YE’25.
Most shorted – June 30, 2026
| Biotech | Ticker | Short Interest (Days to Cover) |
| Coherus Oncology | CHRS | 21.9 |
| Atea Pharmaceuticals | AVIR | 16.0 |
| Tectonic Therapeutics | TECX | 14.3 |
| Neurogene | NGNE | 13.5 |
| Autolus Therapeutics | AUTL | 13.3 |
Source: Nasdaq, New Street Investor Relations
- Within “small” biotechs, Coherus was the most shorted stock on June 30, 2026, at 21.9 Days to Cover, with Atea, Tectonic, Neurogene and Autolus rounding out the top five.
Least shorted – June 30, 2026
| Biotech | Ticker | Short Interest (Days to Cover) |
| Neumora Therapeutics | NMRA | 1.1 |
| Fulcrum Therapeutics | FULC | 1.5 |
| Esperion Therapeutics | ESPR | 1.7 |
| Silence Therapeutics | SLN | 2.2 |
| Maravai Lifesciences | MRVI | 2.3 |
Source: Nasdaq, New Street Investor Relations
- At the other end of the spectrum, Neumora was the least shorted “small” biotech at 1.1 Days to Cover, with Fulcrum, Esperion, Silence and Maravai rounding out the five least shorted companies.
Medium Biotech ($1B-$2.5B), n=66
| Date | December 31, 2024 | June 30, 2025 | December 31, 2025 | June 30, 2026 |
| Average Short Interest (Days to Cover) | 9.4 | 8.7 | 9.0 | 7.2 |
Source: Nasdaq, New Street Investor Relations
- At 1H’26, the average (mean) short interest in a “medium” biotech was 7.2 Days to Cover versus 9.0 Days to Cover at YE’25.
Most shorted – June 30, 2026
| Biotech | Ticker | Short Interest (Days to Cover) |
| Lakefront Bio | LKFT | 15.8 |
| Mesoblast | MESO | 14.9 |
| Savara | SVRA | 12.6 |
| Immunocore | IMCR | 12.5 |
| Corvus Pharma | CRVS | 12.4 |
Source: Nasdaq, New Street Investor Relations
- Within “medium” biotechs, Lakefront Bio was the most shorted stock on June 30, 2026, at 15.8 Days to Cover, with Mesoblast, Savara, Immunocore and Corvus completing the top five.
Least shorted – June 30, 2026
| Biotech | Ticker | Short Interest (Days to Cover) |
| Alvotech | ALVO | 2.2 |
| Pharvaris | PHVS | 2.3 |
| AtaiBeckley | ATAI | 2.4 |
| Personalis | PSNL | 2.8 |
| MeiraGTx | MGTX | 3.0 |
Source: Nasdaq, New Street Investor Relations
- Turning to the least shorted “medium” biotechs at 1H’26, Alvotech was the least shorted at 2.2 Days to Cover, followed by Pharvaris, AtaiBeckley, Personalis and MeiraGTx.
Large Biotechs ($2.5B-$10B), n=57
| Date | December 31, 2024 | June 30, 2025 | December 31, 2025 | June 30, 2026 |
| Average Short Interest (Days to Cover) | 8.8 | 7.2 | 8.1 | 5.6 |
Source: Nasdaq, New Street Investor Relations
- Lastly, at 1H’26, the average (mean) short interest in a “large” biotech was 5.6 Days to Cover versus 8.1 Days to Cover at YE’25.
Most shorted – June 30, 2026
| Biotech | Ticker | Short Interest (Days to Cover) |
| Crispr Therapeutics | CRSP | 11.7 |
| Grail | GRAL | 11.1 |
| Crinetics Pharmaceuticals | CRNX | 9.2 |
| ImmunityBio | IBRX | 8.7 |
| Immunovant | IMVT | 8.6 |
Source: Nasdaq, New Street Investor Relations
- Within “large” biotechs, Crispr was the most shorted stock on June 30, 2026, at 11.7 Days to Cover, followed by Grail, Crinetics, ImmunityBio, and Immunovant.
Least shorted – June 30, 2026
| Biotech | Ticker | Short Interest (Days to Cover) |
| Apogee Therapeutics | APGE | 1.0 |
| Nuvalent | NUVL | 1.2 |
| Definium Therapeutics | DFTX | 2.1 |
| Adaptive Biotechnologies | ADPT | 2.2 |
| Uniqure | QURE | 2.6 |
Source: Nasdaq, New Street Investor Relations
- Turning to the least shorted “large” biotechs at 1H’26, Apogee was the least shorted at 1.0 Days to Cover, followed by Nuvalent, Definium, Adaptive Biotechnologies, and Uniqure.
Conclusions
- Overall, the average short interest across “small” (6.3), “medium” (7.2) and “large” (5.6) biotechs fell to approximately 6 Days to Cover – approximately two Days to Cover lower than reported at both YE’25 and 1H’25.