RTW Investments
Based on Q4 2025 SEC Form 13F filings, RTW Investments manages a portfolio with 91 disclosed long equity positions. The fund's 13F market value sits at $10.00B, reflecting a decline in quarter-over-quarter AUM. Ranked by portfolio weight, the top holdings are MADRIGAL PHARMACEUTICALS INC (MDGL) at 11.63%, INSMED INC (INSM) at 8.44%, and PTC THERAPEUTICS INC (PTCT) at 5.89%. The fund is primarily focused on the Healthcare sector. New positions this quarter include IRHYTHM TECHNOLOGIES INC (IRTC) , APELLIS PHARMACEUTICALS INC (APLS) , REPLIGEN CORP (RGEN) , INSULET CORP (PODD) , and CASTLE BIOSCIENCES INC (CSTL) . Fully exited positions include AVIDITY BIOSCIENCES INC (SYN_05370A108) , AKERO THERAPEUTICS INC (SYN_00973Y108) , MERUS N V (SYN_N5749R100) , QUEST DIAGNOSTICS INC (DGX) , and LENZ THERAPEUTICS INC (LENZ) . Ranked by the share of each peer fund's 13F equity portfolio that overlaps with RTW Investments's disclosed positions as of Q4 2025, the closest peers are Darwin Global Management (86.6%), Deep Track (49.1%), and Baker Bros. Advisors (40.8% overlap).
- 13F AUM
- $10.0B
- Equity Positions
- 91
- Top-10 Concentration
- 50.5%
- Largest Sector · 99.2%
- Healthcare
- Longest held · 40 qtrs
- MASI
- Median Holding Period
- 4 Qtrs
Top 10 HoldingsQ4 2025
Ranked by portfolio weight. Δ QoQ is the change in weight versus the previous reporting quarter.
| # | Ticker | Company | Sector | Shares | Weight | Δ QoQ | Market Value |
|---|---|---|---|---|---|---|---|
| 1 | MDGL | Healthcare | 1,993,687 | 11.63% | +0.36% | $1.16B | |
| 2 | INSM | Healthcare | 4,842,879 | 8.44% | +2.97% | $842.9M | |
| 3 | PTCT | Healthcare | 7,746,415 | 5.89% | +0.04% | $588.4M | |
| 4 | ARGX | Healthcare | 673,497 | 5.67% | -0.45% | $566.4M | |
| 5 | PTGX | Healthcare | 5,059,053 | 4.43% | -0.29% | $441.9M | |
| 6 | NTRA | Healthcare | 1,500,000 | 3.44% | -0.52% | $343.6M | |
| 7 | RDNT | Healthcare | 3,938,500 | 2.81% | +0.17% | $281.0M | |
| 8 | TARS | Healthcare | 3,335,320 | 2.74% | +0.41% | $273.1M | |
| 9 | COGT | Healthcare | 7,592,241 | 2.70% | +2.09% | $269.7M | |
| 10 | PEN | Healthcare | 866,499 | 2.70% | -0.01% | $269.4M |
Quarterly shiftsvs previous quarter
Top movers in RTW Investments's Form 13F versus the prior reporting quarter. Δ Weight is the change in portfolio weight (percentage points); Δ Shares is the percent change in share count.
| Company | Ticker | Δ Weight | Δ Shares |
|---|---|---|---|
| INSMED INC | INSM | +2.97% | +57.00% |
| COGENT BIOSCIENCES INC | COGT | +2.09% | +118.96% |
| BELITE BIO INC | BLTE | +0.86% | +128.91% |
| APOGEE THERAPEUTICS INC | APGE | +0.72% | +0.00% |
| SPYRE THERAPEUTICS INC | SYRE | +0.62% | +15.18% |
| Company | Ticker | Δ Weight | Δ Shares |
|---|---|---|---|
| UNIQURE NV | QURE | -2.29% | -16.12% |
| STRYKER CORPORATION | SYK | -1.37% | -50.00% |
| INTUITIVE SURGICAL INC | ISRG | -0.54% | -50.00% |
| NATERA | NTRA | -0.52% | -25.00% |
| ULTRAGENYX PHARMACEUTICAL IN | RARE | -0.52% | -7.92% |
| Company | Ticker | New weight |
|---|---|---|
| IRHYTHM TECHNOLOGIES INCNEW | IRTC | 2.10% |
| APELLIS PHARMACEUTICALS INCNEW | APLS | 1.93% |
| REPLIGEN CORPNEW | RGEN | 1.75% |
| INSULET CORPNEW | PODD | 0.92% |
| CASTLE BIOSCIENCES INCNEW | CSTL | 0.82% |
| Company | Ticker | Prev weight |
|---|---|---|
| AVIDITY BIOSCIENCES INC | SYN_05370A108 | 6.11% |
| AKERO THERAPEUTICS INC | SYN_00973Y108 | 3.20% |
| MERUS N V | SYN_N5749R100 | 2.35% |
| QUEST DIAGNOSTICS INC | DGX | 0.59% |
| LENZ THERAPEUTICS INC | LENZ | 0.50% |
Portfolio composition
Sectors, concentrations, and a tap-through treemap of every position in the fund's latest 13F.
Quarterly shifts
Top movers versus the prior reporting quarter. Left panel bridges market-value change in USD millions; right panel shows share-count change in %.
Holding period analytics
Distribution of holding periods for all 394 stocks the fund has ever held (up to selected quarter):
Peer Group — Funds With Most Portfolio Overlap
Ranked by percentage of the peer fund's 13F equity portfolio that overlaps with RTW Investments's positions in Q4 2025.
| # | Fund | Shared Positions | Overlap % |
|---|---|---|---|
| 1 | Darwin Global Management | 4 | 86.6% |
| 2 | Deep Track | 20 | 49.1% |
| 3 | Baker Bros. Advisors | 26 | 40.8% |
| 4 | Exome Asset Management | 18 | 37.2% |
| 5 | Commodore Capital | 10 | 32.0% |
13F AUM Development
Quarterly 13F-reported equity AUM for RTW Investments, derived from aggregate long equity position market values disclosed to the U.S. SEC.
Methodology & FAQ
How We Track RTW Investments Holdings
Our data is systematically aggregated directly from quarterly Form 13F-HR disclosures submitted to the U.S. Securities and Exchange Commission (SEC).
- Who Must File (Reporting Threshold): This dataset includes filings from U.S. institutional investment managers, hedge funds, mutual funds, university endowments, and family offices managing at least $100 million in qualifying discretionary U.S. equities.
- What is Included (Data Scope): We exclusively capture long equity positions and listed options (calls and puts) for RTW Investments. By SEC regulation, 13F filings do not require the disclosure of short positions, non-U.S. holdings, or OTC derivatives.
- Portfolio Weight Explained (Metric Definition): “Portfolio Weight” shows how much of a fund's total 13F U.S. equity portfolio is allocated to a specific position on the reporting date.
- How to Use This Data (Interpretation): Quarter-over-quarter changes in shares and portfolio weight reflect a combination of active trading and market price movements. These are descriptive metrics of fund allocation, not explicit buy or sell signals.
How do you measure hedge fund conviction in RTW Investments's portfolio?
We evaluate conviction by looking at portfolio weight rather than just absolute share count. A position that represents a large percentage of a fund's total 13F equity value signals high conviction, regardless of whether it ranks highly in absolute dollar terms. Tracking how this weight changes quarter-over-quarter helps distinguish active capital allocation from passive drift.
Does RTW Investments's 13F data include short positions or derivatives?
SEC Form 13F only mandates the disclosure of long U.S. equity positions and listed options (put and call contracts). Short interest, swaps, and OTC derivatives are excluded by regulatory design. To ensure accurate position scaling, listed options are reported based on their underlying share equivalent.
Are family offices and endowments included in this data?
Yes. Any institutional entity exercising investment discretion over at least $100 million in qualifying U.S. equities must file a Form 13F — this explicitly includes single-family offices and university endowments. If a qualifying entity holds positions reported by RTW Investments, their allocation is included in this dataset.
When is the data updated, and is there a reporting lag?
Institutional investment managers are required to file their Form 13F within 45 days after the end of each calendar quarter (the standard “T+45” window). Our platform processes filings immediately upon publication to the SEC EDGAR database, providing point-in-time consensus positioning without look-ahead bias.
Data Source: Aggregated from public SEC Form 13F filings via the EDGAR database.