Paradigm Biocapital Advisors LP: ARCELLX INC (ACLX): Quarterly 13F Position History
As of Q1 2026, Paradigm Biocapital Advisors LP reported 5,774,016 shares of ARCELLX INC (ACLX), worth $663.0M and representing 13.5% of its 13F equity book. Quarter-over-quarter share count change: + 50,000 (+0.9%) . The position first appeared in Q4 2022 and has been disclosed across 14 13F-HR filings in Pactolio's tracked window.
- 5,774,016Shares Held (Latest Filing)
- $663.0MReported Market Value (Latest Filing)
- 13.5%Portfolio Weight (% of 13F Equity Book)
- +50,000Quarter-over-Quarter Share Change
- +$289.8MQuarter-over-Quarter Value Change
- 5,774,016Peak Reported Shares (Historical)
Quarterly 13F-HR Disclosure History Source: SEC 13F-HR filings, 14 quarter s
| Quarter | Shares | QoQ Share Change | Share Change (%) | Market Value | Weight | Implied Price |
|---|---|---|---|---|---|---|
| Q1 2026 | 5,774,016 | +50,000 | +0.9% | $663.0M | 13.5% | $114.8 |
| Q4 2025 | 5,724,016 | +1,075,000 | +23.1% | $373.2M | 10.0% | $65.2 |
| Q3 2025 | 4,649,016 | 0 | — | $381.7M | 11.3% | $82.1 |
| Q2 2025 | 4,649,016 | +156,984 | +3.5% | $306.1M | 13.1% | $65.8 |
| Q1 2025 | 4,492,032 | +120,431 | +2.8% | $294.7M | 13.6% | $65.6 |
| Q4 2024 | 4,371,601 | +371,601 | +9.3% | $335.3M | 11.7% | $76.7 |
| Q3 2024 | 4,000,000 | +151,905 | +3.9% | $334.0M | 11.7% | $83.5 |
| Q2 2024 | 3,848,095 | +30,000 | +0.8% | $212.4M | 8.1% | $55.2 |
| Q1 2024 | 3,818,095 | +159,471 | +4.4% | $265.5M | 9.3% | $69.5 |
| Q4 2023 | 3,658,624 | +705,502 | +23.9% | $203.1M | 9.5% | $55.5 |
| Q3 2023 | 2,953,122 | +606,122 | +25.8% | $106.0M | 7.2% | $35.9 |
| Q2 2023 | 2,347,000 | +589,221 | +33.5% | $74.2M | 6.0% | $31.6 |
| Q1 2023 | 1,757,779 | +875,678 | +99.3% | $54.2M | 5.1% | $30.8 |
| Q4 2022 | 882,101 | — | — | $27.3M | 3.2% | $31.0 |
Methodology & FAQ
How This Position History Is Sourced
Each row is one SEC Form 13F-HR filing disclosing this position. Share count, market value, and reported quarter are taken verbatim from the filing; portfolio weight is recomputed against the same filing's total reported equity book. Implied price-per-share is market value divided by shares — a quarter-end mark, not the manager's cost basis. See the full methodology document for the normalization rules.
When did Paradigm Biocapital Advisors LP first disclose a ACLX position in 13F-HR filings?
Paradigm Biocapital Advisors LP first reported ARCELLX INC (ACLX) on its 13F-HR filing for the period ending 2022-12-31 (Q4 2022). The position has appeared on 14 reported quarters within Pactolio's tracked window.
What was Paradigm Biocapital Advisors LP's most recent quarter-over-quarter share-count change in ACLX?
Between Q4 2025 and Q1 2026, Paradigm Biocapital Advisors LP added 50,000 shares of ACLX (+0.9%), bringing the total reported position to 5,774,016 shares at a market value of $663.0M.
Does the implied price-per-share represent Paradigm Biocapital Advisors LP's cost basis in ACLX?
No. The implied price-per-share column is the 13F-HR reported market value divided by reported share count on the filing date (end of quarter). It is a quarter-end mark, not a cost basis or transaction price. Use it as a sanity check on the value column, not as an indicator of the manager's entry or exit price.