RTW INVESTMENTS, LP: ARGENX SE (ARGX): Quarterly 13F Position History
As of Q1 2026, RTW INVESTMENTS, LP reported 709,446 shares of ARGENX SE (ARGX), worth $518.1M and representing 5.2% of its 13F equity book. Quarter-over-quarter share count change: + 35,949 (+5.3%) . The position first appeared in Q2 2017 and has been disclosed across 36 13F-HR filings in Pactolio's tracked window.
- 709,446Shares Held (Latest Filing)
- $518.1MReported Market Value (Latest Filing)
- 5.2%Portfolio Weight (% of 13F Equity Book)
- +35,949Quarter-over-Quarter Share Change
- -$48.3MQuarter-over-Quarter Value Change
- 709,446Peak Reported Shares (Historical)
Quarterly 13F-HR Disclosure History Source: SEC 13F-HR filings, 36 quarter s
| Quarter | Shares | QoQ Share Change | Share Change (%) | Market Value | Weight | Implied Price |
|---|---|---|---|---|---|---|
| Q1 2026 | 709,446 | +35,949 | +5.3% | $518.1M | 5.2% | $730.3 |
| Q4 2025 | 673,497 | 0 | — | $566.4M | 5.7% | $841.0 |
| Q3 2025 | 673,497 | 0 | — | $496.7M | 6.1% | $737.6 |
| Q2 2025 | 673,497 | 0 | — | $371.2M | 5.3% | $551.2 |
| Q1 2025 | 673,497 | 0 | — | $398.6M | 6.1% | $591.9 |
| Q4 2024 | 673,497 | +19,067 | +2.9% | $414.2M | 6.3% | $615.0 |
| Q3 2024 | 654,430 | 0 | — | $354.8M | 5.1% | $542.1 |
| Q2 2024 | 654,430 | 12,765 | -1.9% | $281.4M | 4.4% | $430.0 |
| Q1 2024 | 667,195 | 0 | — | $262.7M | 3.9% | $393.7 |
| Q4 2023 | 667,195 | +160,000 | +31.5% | $253.8M | 4.0% | $380.4 |
| Q3 2023 | 507,195 | +25,000 | +5.2% | $249.4M | 5.3% | $491.6 |
| Q2 2023 | 482,195 | 0 | — | $187.9M | 3.6% | $389.7 |
| Q1 2023 | 482,195 | 0 | — | $179.7M | 3.7% | $372.6 |
| Q4 2022 | 482,195 | +15,000 | +3.2% | $182.7M | 3.7% | $378.8 |
| Q3 2022 | 467,195 | +24,560 | +5.5% | $164.9M | 3.8% | $353.0 |
| Q2 2022 | 442,635 | +105,657 | +31.4% | $167.7M | 4.3% | $378.9 |
| Q1 2022 | 336,978 | +19,531 | +6.2% | $106.3M | 2.2% | $315.3 |
| Q4 2021 | 317,447 | +177,136 | +126.2% | $111.2M | 1.6% | $350.2 |
| Q3 2021 | 140,311 | +108,559 | +341.9% | $42.4M | 0.6% | $302.0 |
| Q2 2021 | 31,752 | 0 | — | $9.6M | 0.1% | $301.1 |
| Q1 2021 | 31,752 | 0 | — | $8.7M | 0.1% | $275.4 |
| Q4 2020 | 31,752 | 0 | — | $9.3M | 0.2% | $294.1 |
| Q3 2020 | 31,752 | 0 | — | $8.3M | 0.2% | $262.5 |
| Q2 2020 | 31,752 | 0 | — | $7.2M | 0.2% | $225.2 |
| Q1 2020 | 31,752 | 0 | — | $4.2M | 0.2% | $131.7 |
| Q4 2019 | 31,752 | +236 | +0.7% | $5.1M | 0.2% | $160.5 |
| Q3 2019 | 31,516 | +68 | +0.2% | $3.6M | 0.2% | $114.0 |
| Q2 2019 | 31,448 | +734 | +2.4% | $4.5M | 0.2% | $141.6 |
| Q1 2019 | 30,714 | +1,937 | +6.7% | $3.8M | 0.3% | $124.8 |
| Q4 2018 | 28,777 | +1,924 | +7.2% | $2.8M | 0.3% | $96.1 |
| Q3 2018 | 26,853 | +1,294 | +5.1% | $2.0M | 0.1% | $75.9 |
| Q2 2018 | 25,559 | +102 | +0.4% | $2.1M | 0.2% | $82.9 |
| Q1 2018 | 25,457 | +197 | +0.8% | $2.0M | 0.2% | $80.4 |
| Q4 2017 | 25,260 | +354 | +1.4% | $1.6M | 0.3% | $63.1 |
| Q3 2017 | 24,906 | 64 | -0.3% | $563.0K | 0.1% | $22.6 |
| Q2 2017 | 24,970 | — | — | $530.0K | 0.1% | $21.2 |
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 RTW INVESTMENTS, LP first disclose a ARGX position in 13F-HR filings?
RTW INVESTMENTS, LP first reported ARGENX SE (ARGX) on its 13F-HR filing for the period ending 2017-06-30 (Q2 2017). The position has appeared on 36 reported quarters within Pactolio's tracked window.
What was RTW INVESTMENTS, LP's most recent quarter-over-quarter share-count change in ARGX?
Between Q4 2025 and Q1 2026, RTW INVESTMENTS, LP added 35,949 shares of ARGX (+5.3%), bringing the total reported position to 709,446 shares at a market value of $518.1M.
Does the implied price-per-share represent RTW INVESTMENTS, LP's cost basis in ARGX?
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.