Joseph Edelman (Perceptive Advisors LLC) reported a total AUM of $3.6B across 20 positions in his Q1 2026 13F filing. PRAX remained the top holding at $656M (12.9% of portfolio), while 5 new positions were initiated — including MRNA ($51M) and IONS ($38M) — and 5 positions were fully liquidated, including XBI ($134M) and BSX ($93M).
Top 5 Holdings — Q1 2026
- PRAX: $656M (12.9%)
- CELC: $357M (7.0%)
- ASCENDIS PHARMA A/S: $350M (6.9%)
- ROIV: $230M (4.5%)
- CNTA: $209M (4.1%)
Q1 2026 Key Trading Highlights
Edelman's portfolio maintained its characteristically concentrated biotech focus. PRAX (12.9%), CELC (7.0%), and Ascendis Pharma (6.9%) occupied the top three slots, collectively representing approximately 27% of total AUM. Notably, Ascendis Pharma saw a 42% increase in position size versus the prior quarter, signaling a high-conviction reassessment of the name as a growth holding. ROIV (+4%, $230M) and PRAX (+2%) also saw modest position increases.
- PRAX: Added +2%, $656M (12.9%) — Unchanged as portfolio's #1 conviction bet on rare neurological diseases
- ASCENDIS PHARMA: Added +42%, $350M (6.9%) — Reflects strong conviction in rare endocrine pipeline; most aggressive add of the quarter
- MRNA: New position $51M — Re-rating of the mRNA platform; entry timed during share price pullback
- IONS: New position $38M — Initiates stake in the leading antisense oligonucleotide platform
- XBI: Full exit $134M → $0 — Eliminates broad ETF exposure in favor of pure single-stock selection
- BSX: Full exit $93M → $0 — Liquidates large-cap medical device name; sharpens portfolio toward biopharma
- NBIX: Reduced -80%, $9M — Aggressive trim effectively minimizes the position
The scale of portfolio cleanup was equally notable. The full liquidation of sector ETF XBI — previously valued at $134M — signals a deliberate strategic shift away from broad-based biotech exposure toward high-conviction individual stock selection. The exit from large-cap medical device name BSX ($93M) further narrows the portfolio's scope to pure-play biopharma and rare disease. Significant reductions in NBIX (-80%, $9M) and OMDA (-67%, $10M) also appear consistent with active risk management and position rightsizing.
Outlook: Deepening Single-Stock Concentration in Rare Disease
In Q1 2026, Edelman exited ETF and large-cap medical device positions to further concentrate the portfolio in individual biopharma names. New initiations in MRNA, IONS, and RVMD suggest a diversified thematic bet across next-generation therapeutic platforms — including mRNA, nucleic acid therapies, and rare oncology. Within a $3.6B AUM framework, the top 3 holdings accounting for roughly 27% of assets creates a high-conviction, high-volatility structure — one that carries meaningful upside if pipeline catalysts play out. Upcoming clinical data readouts from PRAX and CELC will likely serve as the portfolio's most critical performance drivers going forward.
