November 7, 2026. Follow-up to the ten-year 13F study. Companies: Revolution Medicines, BeiGene, Madrigal and Celcuity. This is a reconstruction of the public investment case at each historical date, not a claim to know Baker's internal reasoning or trade dates.
The recurring opportunity was to increase exposure when human evidence made the next development step underwritable, while substantial clinical and commercial uncertainty remained. But BeiGene needs a material correction: its apparent Q2 2018 accumulation was a security conversion. Celcuity also differs from the others because much of its build preceded the pivotal result.
I retrieved 356 filing documents and exhibits using sec-api and the local 8krecents.py parser, reconciled the existing quarterly ownership archive, and read Revolution's November 6, 2024 earnings transcript. Historical issuer releases and SEC exhibits provide the core evidence for the other companies; the local library did not supply contemporaneous earnings transcripts for their relevant windows. The analyst questions below are my reconstruction unless explicitly attributed to an actual transcript participant. Later successful outcomes are not evidence investors possessed during the build.
| Case |
What actually happened to ownership |
What became more credible |
Remaining leap |
| Revolution, 2023–Q1 2024 |
222,222 shares at year-end 2022 → 2,691,493 Q1 2023 → 5,148,657 Q4 2023 → 7,549,249 Q1 2024 |
RAS(ON) inhibition could generate human tumor responses across several mutations; development could be funded |
Durability, dose selection and randomized benefit |
| BeiGene, January 2018 |
Purchased 1,980,198 ADSs at $101, about $200m; the following Q2 increase of 6,130,395 ADSs was conversion of existing ordinary shares |
A differentiated BTK candidate plus a financed, global oncology organization and Chinese commercial infrastructure |
Comparative clinical superiority, regulatory execution and commercial adoption |
| Madrigal, Q4 2017–Q2 2018 |
57,762 shares → 615,684 → 1,169,278 |
Liver-fat reduction was followed by biopsy evidence of disease improvement |
Reproduction in a larger pivotal trial, long-term safety and an agreed regulatory path |
| Celcuity, 2024–2025 |
535,478 shares at year-end 2023 → 2,678,553 at year-end 2024 → 5,450,445 before July 2025 data → 7,915,792 at Q3-end |
A promising early breast-cancer combination approached a randomized test, then delivered a positive result |
Before July: reproducibility; afterward: approval, competitive positioning and commercialization |
Sources for reported inventories: Baker quarterly archive (holdings workbook), with each underlying SEC filing URL retained; focused ownership reconciliation. BeiGene transaction evidence: January 22, 2018 13D and August 1, 2018 13D. Clinical evidence is detailed below.
At the start of 2023, the investor was looking at two different stories inside the company. Its older SHP2 inhibitor, RMC-4630, had lost Sanofi's commitment: Sanofi had given notice to terminate the collaboration, effective June 2023. Meanwhile, the first RAS(ON) drugs, RMC-6236 and RMC-6291, had entered clinical testing in 2022. The question was whether directly inhibiting active RAS could work at doses patients could tolerate. Success would potentially extend beyond the G12C segment addressed by the earlier generation of RAS drugs. This was a change in the source of potential value, with a disappointing older partnership alongside encouraging new compounds. February 27, 2023 update.
That February update offered unusually early evidence: 36 patients were evaluable for safety and 12 for efficacy at selected dose levels. All 12 had stable disease or better; 10 had tumor shrinkage. A lung-cancer response was confirmed, while a striking pancreatic-cancer response still awaited confirmation. Management described dosing at “clinically active and tolerated doses.” An analyst should have regarded this as evidence of biological activity and a possible therapeutic window, not an established response rate or survival benefit. The sample was tiny, uncontrolled and immature. Same dated clinical update.
Baker's first major increase occurred in that quarter: 222,222 to 2,691,493 shares. A March financing sold stock at $22 per share, providing additional development capital. Those events coincide; the 13F does not establish Baker's exact execution dates or its allocation in that financing. Q1 2023 13F; March financing 8-K.
By October 2023 the question had advanced. The company presented RMC-6236 response rates of 38% in 40 evaluable lung-cancer patients and 20% in 46 pancreatic-cancer patients. Those headline rates included unconfirmed responses; 12 of 15 lung responses and five of nine pancreatic responses were confirmed at that cut. Evidence across G12D, G12V and G12R mattered because it supported broader applicability rather than one exceptional patient or mutation. The outstanding concern was whether responses would last and produce a randomized benefit. October 22 presentation, filed October 23.
Financing risk also changed. The EQRx acquisition brought a large cash infusion, and Revolution subsequently reported $1.85bn of cash and investments at year-end 2023 with projected runway into 2027. Its February 2024 update described response-rate trends in the low-to-mid-40% range for lung cancer and mid-20% range for pancreatic cancer, alongside plans for pivotal trials. Baker reached 7.55m shares by March 2024. My interpretation: the increased position is consistent with underwriting a funded development program after initial human validation, well before randomized proof. February 26, 2024 update; Q1 2024 13F.
The actual analyst dialogue later in the build period illustrates what still mattered. On November 6, 2024, TD Cowen's Marc Frahm pressed management on why the lung and pancreatic pivotal-study timelines had diverged. Leerink's Jonathan Chang asked which studies the cash-runway forecast actually funded. Management said the two second-line Phase III programs were fully included; other potential programs used probability-adjusted cost assumptions. The debate had progressed from early activity toward development design, execution and capital allocation. Those November observations should not be backdated as knowledge available during the Q1 build. November 6, 2024 transcript (source note).
BeiGene — a real $200m investment in an emerging oncology company, but not the apparent tripling of exposure.
The ownership correction changes the case materially. Baker's January 2018 purchase was 1,980,198 ADSs at $101. Its August 13D explains that existing ordinary shares became 502,548 and 5,627,847 ADSs for its two funds, “without consideration and without a change in pecuniary interest.” Their sum, 6,130,395, exactly equals the Q1-to-Q2 increase in reported ADS inventory. The January purchase increased the two funds' underlying ordinary-share-equivalent holding by approximately 19.8%, not threefold. Baker already had board representatives before the IPO and substantial ordinary-share ownership outside the 13F ADS line. This was additional commitment to an established investment. January purchase; conversion and board history.
What could an investor see in January? First, zanubrutinib had a differentiated scientific proposition in an already validated drug class. BeiGene's January presentation emphasized sustained BTK occupancy in lymph-node tissue and a potential tolerability advantage over existing inhibitors. The meaningful questions were whether target coverage would translate into deeper, more durable responses, and whether lower off-target effects could keep patients on treatment longer. Its comparison with other drugs was largely based on separate datasets; prospective comparative proof remained ahead. January 2018 investor presentation.
Second, the company was becoming capable of developing and selling multiple drugs. The July 2017 Celgene agreement provided $263m in upfront license fees and a $150m equity investment, transferred Celgene's Chinese commercial operations, and licensed Abraxane, Revlimid and Vidaza for China. It also partnered tislelizumab outside much of Asia for solid tumors. This simultaneously supplied outside validation, capital and a commercial organization. It did not prove that BeiGene's own investigational drugs would succeed. July 2017 agreement.
The January financing therefore funded a portfolio and an organization: zanubrutinib, tislelizumab and pamiparib were entering or expanding pivotal development. By May, BeiGene reported more than 30 trials and plans for its first Chinese drug applications that year. Q1 product revenue of $23.25m came from the licensed commercial portfolio, not sales of an approved proprietary zanubrutinib franchise. January company overview; May 9, 2018 quarterly update.
June data further strengthened the development case: the Chinese pivotal mantle-cell lymphoma study reported an 84% response rate and 59% complete-response rate in 86 patients. A pooled safety analysis covered 476 patients, while the head-to-head Waldenström study against ibrutinib had met its enrollment target. These were encouraging clinical and regulatory steps, but comparative superiority was still unproven. They also arrived after the documented January purchase and cannot explain a supposed Q2 purchase that did not occur. June 15, 2018 development update.
My interpretation: the genuine January investment was consistent with backing a potentially differentiated BTK franchise inside an increasingly credible global oncology business. The lesson from Q2 is about reconciling securities, not reading conviction from an unadjusted 13F chart.
Madrigal — evidence progressed from reducing liver fat to improving liver disease.
The initial Madrigal holding was inherited from Synta through the merger and reverse split, not necessarily an intentional small position in the new NASH thesis. Baker held approximately 57,762 post-merger shares through Q3 2017. Its first material enlargement came in Q4, when the count reached 615,684, followed by 1,169,278 in Q2 2018. Earlier study and merger evidence; Q4 2017 13F; Q2 2018 13F.
The contemporary scientific proposition was that a liver-directed, thyroid-hormone-receptor-beta agonist could improve hepatic metabolism while avoiding liabilities associated with less selective thyroid-hormone approaches. MGL-3196, subsequently called resmetirom, was being developed for NASH and dyslipidemia. For an analyst, this offered a large disease opportunity, but efficacy, chronic safety and the eventual approval standard were still uncertain. The 2017 prospectus explicitly warned that pivotal endpoints could differ from the current trial and that accelerated approval was not assured. December 2017 prospectus.
The first important step was the December 2017 liver-fat result. At 12 weeks, median relative liver-fat reduction was 36.3% with MGL-3196 versus 9.6% with placebo. The analysis also showed improvements in lipids and liver-related biomarkers. This made the drug's metabolic activity more credible, but MRI-measured fat reduction alone did not establish histological improvement or an approvable medicine. A financing later that month priced at $83 per share. Baker's Q4 increase overlapped both the readout and financing; exact purchase timing is not established by the quarter-end holding. December prospectus, clinical results and offering terms.
The second step, on May 31, 2018, was more relevant to disease modification. The reported biopsy analysis showed NASH resolution in 27% of treated patients versus 6.5% of placebo patients, with 73 and 34 paired-biopsy patients respectively. Among treated patients whose early liver-fat reduction reached the specified threshold, resolution was higher. The important inference was a possible connection between an early noninvasive marker and later tissue improvement. The trial remained small; the responder subgroup was not the overall result, and this was not definitive proof of an antifibrotic benefit. May 31, 2018 original topline disclosure.
That progression changed the underwriting question from “does the molecule reduce hepatic fat?” to “can a larger trial reproduce clinically and regulatorily meaningful histology?” Capital then supported the attempt: the June offering priced at $305, and the company later reported $311.8m of net proceeds and $490.3m of quarter-end cash and securities. The August report described a substantially financed development program; as of November, management still expected Phase III to start in late 2018 or early 2019, subject to regulatory approval. June offering; August financial update; November development update.
My interpretation: this is the clearest example of adding around successive improvements in the quality of evidence. The required leap narrowed from biological activity to reproducible disease improvement, while substantial pivotal and regulatory risk remained. It was not simply buying the stock at its cheapest: the reported quarter-end mark rose from $91.79 in Q4 2017 to $279.69 in Q2 2018 while Baker almost doubled its shares. These are quarter-end marks, not its execution prices. Verified holdings calculations.
Celcuity — building through uncertainty before the randomized answer, then continuing in the quarter of success.
The underlying idea was that gedatolisib could inhibit the PI3K/AKT/mTOR signaling pathway more comprehensively than drugs targeting one component, and work alongside endocrine therapy and CDK4/6 inhibition. Celcuity emphasized activity both with and without PIK3CA mutations. That raised the possibility of treating a broader breast-cancer population than a mutation-limited approach. Its intravenous administration and intermittent schedule were part of the proposed pharmacological advantage, but also a potential commercial inconvenience. 2023 10-K filed March 27, 2024.
There was more than a mechanism diagram to study. The earlier Phase Ib trial's Arm D, relevant to previously CDK4/6-treated patients, reported median progression-free survival of 12.9 months and an evaluable response rate of 63%. Early safety data also suggested a workable tolerability profile. But this was a small, nonrandomized combination study. The analyst needed to examine patient selection, prior therapies, dosing, adverse-event discontinuations and the contribution of each drug. Comparing these results with another trial's control arm could generate a hypothesis, not prove superiority. Contemporaneous 10-K clinical tables.
Baker's first disclosed common-stock position was 535,478 shares in Q3 2023. By Q1 2024 it held 1.55m, while Celcuity still expected the PIK3CA-wild-type portion of VIKTORIA-1 to read out in the second half of 2024. A chief commercial officer was hired, the company was testing a prostate-cancer extension, and management was planning beyond a single study. These were organizational commitments, not clinical proof. March 27, 2024 update; ownership archive.
The uncertainty became visible in changing guidance:
- In August 2024, a lower-than-expected proportion of enrolled patients with wild-type tumors pushed that cohort's expected completion and readout later.
- By November, the wild-type cohort was fully enrolled, with results expected in late Q1 or Q2 2025.
- In March 2025, the expected readout was Q2; in May, the company anticipated Q3.
Sources: August 2024, November 2024, March 2025, May 2025.
An event-driven study arriving later does not by itself reveal which treatment arm is doing better. Enrollment mix, follow-up, event rates in both arms and data handling all matter. Meanwhile, financing reduced immediate funding pressure: the company reported $264m of cash and investments at September 2024 and $235.1m at December, with projected development runway through 2026. Baker increased to 2.68m shares by year-end and 5.45m by June 2025, before the decisive result. November 2024 update; March 2025 update; Q2 2025 13F.
On July 28, the wild-type cohort delivered randomized evidence: median progression-free survival was 9.3 months for the gedatolisib/palbociclib/fulvestrant triplet versus 2.0 months for fulvestrant, with hazard ratio 0.24. The gedatolisib/fulvestrant doublet also met its endpoint. The specific inference was efficacy against the trial's control in this patient population, not superiority over every available breast-cancer regimen. July 28, 2025 topline results.
Baker held 7.92m common shares at September-end. That quarter straddled the readout and subsequent financing, so the 13F cannot tell us how much of its increase occurred before versus after July 28. The company priced a stock/pre-funded-warrant offering at approximately $38 and a convertible-note offering after the result. Baker's common-stock series is not its full exposure to every security. Q3 2025 13F; July financing terms.
My interpretation: Celcuity combines a substantial pre-result increase with further accumulation during the successful readout quarter. The scale needs context. Its June common-stock holding was $72.8m, only 0.71% of Baker's reported 13F book, despite being approximately ten times the starter share count. By September, it was $391m and 2.83%, reflecting both more shares and a higher price. Those percentages are of reported 13F assets, not fund NAV. This looks like risk-bearing conviction with room to expand, rather than an already dominant portfolio bet before the binary event. Ownership reconciliation.
The pattern an investor can actually use.
-
Identify the specific uncertainty that changed. Revolution supplied early human evidence for a new way to inhibit RAS. Madrigal connected an imaging marker to biopsy improvement. BeiGene combined a differentiated clinical hypothesis with execution capacity. Celcuity brought a promising combination to a randomized test. “Good data” is too vague; the issue is which alternative explanation became less plausible.
-
Separate clinical confidence from financial capacity. A promising drug can still be an unattractive equity if the next decisive trial is unfunded or requires heavy dilution. These periods combined scientific progress with meaningful financing or balance-sheet support. Participation in a financing is only proven here where transaction disclosures identify the buyer; a same-quarter share increase is insufficient on its own.
-
Look for a path to a larger business, while treating it as a hypothesis. Multiple RAS mutations and combination regimens; a global BTK/oncology franchise; a chronic metabolic-liver therapy; breast-cancer treatment across mutation groups and earlier lines. A stronger initial result could support a larger addressable opportunity, but those extensions were not yet established products.
-
Do not impose one entry-price pattern. Madrigal's second build occurred across a much higher price environment. Celcuity's holding grew from 1.55m to 4.26m shares while its quarter-end mark fell from $21.60 in Q1 2024 to $10.11 in Q1 2025. The relevant variable appears to be the relationship between evidence, remaining risk and price, not buying every dip or every positive headline. This is an interpretation of the observed series, not a disclosed Baker rule. Quarterly marks and shares.
-
Reconcile what “commitment” means. Shares, dollars, portfolio weight and underlying economic exposure answer different questions. BeiGene's conversion created false accumulation; Madrigal's initial holding came through a merger; Celcuity's tenfold share increase was still a sub-1% reported-book position before data. A first 13F appearance does not establish first ownership or the start of diligence.
The most useful research question for a prospective analogue is: What can I underwrite today that I could not underwrite when this was merely a small position—and is the expected value of that improvement greater than the price increase and financing cost? These selected winners illustrate mechanisms of conviction-building; they do not establish that similar signals reliably predict success without examining failed examples as well.
Source and calculation archive: filing manifest, historical retrieval code (retained in the research archive), ownership reconciliation. The earlier narrative report has been corrected for BeiGene. Its existing workbook remains a raw reported-13F analysis; the Q2 2018 scaling label must be read with the conversion correction above.
As of November 7, 2026. Manager: Baker Bros. Advisors LP, CIK 1263508. Study: Q3 2016 through Q2 2026; Q2 2016 provides the opening baseline. Latest 13F filed August 14, 2026.
Seagen is the clear dominant dollar winner. BeOne/BeiGene and Revolution Medicines form the next tier in the quarterly appreciation screen, followed by Madrigal, Celcuity and Kymera. Incyte, Acadia and Kodiak demonstrate why the largest positions and the biggest winners are different lists.
November 7 follow-up correction — BeiGene: The Q2 2018 increase of 6,130,395 reported ADSs was entirely a conversion of already-owned ordinary shares, not new investment. Baker's August 1, 2018 13D explicitly says this occurred without consideration or a change in pecuniary interest. The genuine January 2018 addition was 1,980,198 ADSs at $101, approximately $200m. The raw 13F counts and workbook remain a record of reported ADS inventory; their Q2 scaling label must not be interpreted as economic accumulation, and the appreciation proxy excludes earlier exposure held as non-ADS ordinary shares. See the corrected build-phase analysis, January purchase disclosure and conversion disclosure.
I examined every reported security in the 40-quarter window: 4,292 original holding rows and 438 CUSIPs, including notes, warrants and other instruments. The common-equity screen contains 408 security lineages after selected corporate-action joins; this is not a claim of 408 distinct businesses. I also retrieved older filings back to Q4 2001 to establish earlier ownership. All 53 structured quarterly information tables from Q2 2013 onward matched the downloaded SEC XML row-for-row, and every cover-page total reconciled. No 13F amendments were returned in the queried history.
Exact investment profits cannot be recovered from 13Fs: they disclose quarter-end inventories, not cost basis, trade prices, distributions or complete private holdings. Consequently, reported position sizes below are observations; the winner figures are explicitly labeled estimates. June 2026 positions must not be treated as November 2026 holdings.
Leading observable dollar winners
The 13F appreciation proxy sums average opening/closing share counts multiplied by the change in quarter-end price, for consecutive quarters with a positive reported holding. Price is reported market value divided by shares. It separates price appreciation from changes in the share count. It does not capture first-ownership-quarter or complete-exit-quarter gains, dividends, financing costs or intraperiod trading. It is neither actual P&L nor a ranking of audited fund returns. Close ranks should not be overinterpreted.
| Investment |
Captured appreciation proxy |
First observed / context |
Largest reported stake in window |
Main accumulation period |
| Seagen Inc. (SGEN) |
$8.279bn |
2003 private; Q3 2004 common 13F |
$9.499bn, 2023 Q1 |
2013–16 and H1 2018 |
| BeOne Medicines Ltd. (ONC) |
$1.820bn |
Q1 2016 public ADS observation; earlier ordinary-share ownership |
$4.236bn, 2021 Q3 |
January 2018 financing; Q2 2018 ADS increase was a conversion |
| Revolution Medicines, Inc. (RVMD) |
$1.585bn |
Q1 2021 |
$2.143bn, 2026 Q2 |
Q1 2023–Q1 2024, then 2025–26 |
| Madrigal Pharmaceuticals, Inc. (MDGL) |
$822.4m |
Synta Q2 2012; Madrigal Q3 2016 |
$1.247bn, 2025 Q4 |
Q4 2017–Q2 2018; Q1 2020; Q4 2023 |
| Celcuity Inc. (CELC) |
$677.8m |
Q3 2023 |
$903.5m, 2026 Q1 |
2024 through Q3 2025 |
| Kymera Therapeutics, Inc. (KYMR) |
$662.4m |
Q3 2020 |
$992.7m, 2026 Q2 |
2022–23 and Q4 2025 |
| Genomic Health, Inc. (GHDX) |
$572.4m |
Q4 2005 |
$968.4m, 2018 Q3 |
Mostly before 2016; trimming in 2018–19 |
| Incyte Corporation (INCY) |
$549.6m |
Already held Q4 2001 |
$4.559bn, 2017 Q1 |
2015–16; 2017 bond exchange; late 2021–Q1 2022 |
| Rhythm Pharmaceuticals, Inc. (RYTM) |
$525.4m |
Q4 2017 |
$622.3m, 2026 Q2 |
2021–22 |
| argenx SE (ARGX) |
$379.9m |
Q2 2017 |
$424.2m, 2022 Q2 |
Q4 2017; mostly trimmed after Q2 2022 |
These estimates are calculated from the complete quarterly holdings series in the accompanying workbook’s Attribution tab. Individual source filings and entry/scaling histories are linked below. The proxy ranking omits final exit quarters and therefore particularly understates takeovers.
Seagen cash outcome: Baker’s final Schedule 13D says the two principal funds, 667 and Baker Brothers Life Sciences, exchanged 1,578,905 and 42,825,004 shares, respectively, for $229 each. That is $10,168,495,161 of gross cash consideration for those two holdings alone. It is not profit; personal, director-compensation and other affiliated holdings are separately described. Baker’s December 2023 exit disclosure.
MyoKardia deserves inclusion among the major winners: the consecutive-quarter proxy is $245.4m, but it stops before BMS’s $225-per-share acquisition in November 2020. The last 13F reported 3,009,344 shares at an implied $136.33. Holding those shares to closing would add approximately $266.8m, giving a roughly $512m combined proxy and $677.1m gross proceeds. This is a stated hold-to-close scenario, not confirmation of Baker’s closing inventory or realized profit. 2020 Q3 13F; BMS completion announcement.
Largest reported positions over the decade
Peak dollar value and peak portfolio weight may occur in different quarters. Values are common-equity positions; weights use the entire reported 13F book as denominator. They are not fund NAV weights.
| Rank |
Investment |
Peak value |
Quarter of peak value |
Peak-ever 13F weight |
First matched public quarter |
| 1 |
Seagen Inc. (SGEN) |
$9.499bn |
2023 Q1 |
54.5% (2023 Q3) |
2004 Q3 |
| 2 |
Incyte Corporation (INCY) |
$4.559bn |
2017 Q1 |
37.6% (2017 Q2) |
2001 Q4 |
| 3 |
BeOne Medicines Ltd. (ONC) |
$4.236bn |
2021 Q3 |
26.5% (2025 Q1) |
2016 Q1 |
| 4 |
ACADIA Pharmaceuticals Inc. (ACAD) |
$2.240bn |
2020 Q4 |
15.3% (2023 Q4) |
2005 Q1 |
| 5 |
Revolution Medicines, Inc. (RVMD) |
$2.143bn |
2026 Q2 |
10.7% (2026 Q2) |
2021 Q1 |
| 6 |
Kodiak Sciences Inc. (KOD) |
$2.039bn |
2020 Q4 |
7.7% (2020 Q4) |
2018 Q4 |
| 7 |
Alexion Pharmaceuticals, Inc. (ALXN) |
$1.369bn |
2020 Q4 |
9.7% (2017 Q3) |
2002 Q4 |
| 8 |
Madrigal Pharmaceuticals, Inc. (MDGL) |
$1.247bn |
2025 Q4 |
7.3% (2025 Q4) |
2012 Q2 |
| 9 |
Insmed Incorporated (INSM) |
$1.214bn |
2026 Q1 |
7.5% (2025 Q2) |
2012 Q4 |
| 10 |
Kymera Therapeutics, Inc. (KYMR) |
$992.7m |
2026 Q2 |
5.0% (2026 Q2) |
2020 Q3 |
| 11 |
Genomic Health, Inc. (GHDX) |
$968.4m |
2018 Q3 |
6.4% (2018 Q3) |
2005 Q4 |
| 12 |
BioMarin Pharmaceutical Inc. (BMRN) |
$936.1m |
2020 Q2 |
5.9% (2017 Q4) |
2006 Q1 |
| 13 |
AbbVie Inc. (ABBV) |
$904.6m |
2016 Q3 |
8.2% (2016 Q3) |
2015 Q2 |
| 14 |
Celcuity Inc. (CELC) |
$903.5m |
2026 Q1 |
5.2% (2026 Q1) |
2023 Q3 |
| 15 |
Amarin Corporation plc (AMRN) |
$897.0m |
2019 Q1 |
5.7% (2019 Q1) |
2015 Q1 |
| 16 |
Prelude Therapeutics Inc. (PRLD) |
$724.0m |
2020 Q4 |
2.7% (2020 Q4) |
2020 Q3 |
| 17 |
Ascendis Pharma A/S (ASND) |
$723.9m |
2021 Q3 |
3.6% (2022 Q4) |
2015 Q1 |
| 18 |
Summit Therapeutics Inc. (SMMT) |
$717.6m |
2025 Q2 |
7.0% (2025 Q2) |
2022 Q4 |
| 19 |
Invitae Corporation (NVTA) |
$654.3m |
2020 Q4 |
2.6% (2021 Q1) |
2015 Q1 |
| 20 |
Rhythm Pharmaceuticals, Inc. (RYTM) |
$622.3m |
2026 Q2 |
4.1% (2025 Q3) |
2017 Q4 |
| 21 |
Praxis Precision Medicines, Inc. (PRAX) |
$587.0m |
2026 Q2 |
3.2% (2026 Q1) |
2022 Q4 |
| 22 |
Alkermes plc (ALKS) |
$524.6m |
2026 Q2 |
2.6% (2026 Q2) |
2015 Q4 |
| 23 |
argenx SE (ARGX) |
$424.2m |
2022 Q2 |
2.4% (2022 Q2) |
2017 Q2 |
| 24 |
AbCellera Biologics Inc. (ABCL) |
$420.5m |
2020 Q4 |
1.6% (2020 Q4) |
2020 Q4 |
| 25 |
MyoKardia, Inc. (MYOK) |
$410.3m |
2020 Q3 |
1.6% (2020 Q3) |
2016 Q3 |
First matched quarter can be a much earlier small holding, a predecessor or a re-entry. The case studies distinguish these. Unlinked CUSIP changes elsewhere in the long tail remain separate security histories.
Latest disclosed positions
The June 30, 2026 13F reported $19.955bn across 84 entries. Its ten largest common-equity positions represented 72.8% of reported value. June 2026 information table.
| Investment |
Value |
13F weight |
Shares / ADSs |
| Incyte Corporation (INCY) |
$3.487bn |
17.5% |
30,762,330 |
| BeOne Medicines Ltd. (ONC) |
$2.508bn |
12.6% |
8,801,567 |
| Revolution Medicines, Inc. (RVMD) |
$2.143bn |
10.7% |
11,443,357 |
| Madrigal Pharmaceuticals, Inc. (MDGL) |
$1.151bn |
5.8% |
2,143,131 |
| ACADIA Pharmaceuticals Inc. (ACAD) |
$1.086bn |
5.4% |
42,912,904 |
| Kymera Therapeutics, Inc. (KYMR) |
$992.7m |
5.0% |
8,657,242 |
| Insmed Incorporated (INSM) |
$937.8m |
4.7% |
8,796,111 |
| Celcuity Inc. (CELC) |
$828.2m |
4.2% |
7,915,792 |
| Kodiak Sciences Inc. (KOD) |
$776.1m |
3.9% |
19,919,186 |
| Rhythm Pharmaceuticals, Inc. (RYTM) |
$622.3m |
3.1% |
5,604,483 |
| Praxis Precision Medicines, Inc. (PRAX) |
$587.0m |
2.9% |
1,753,198 |
| Alkermes plc (ALKS) |
$524.6m |
2.6% |
10,012,267 |
| Summit Therapeutics Inc. (SMMT) |
$477.7m |
2.4% |
32,786,348 |
| GRAIL, Inc. (GRAL) |
$275.0m |
1.4% |
4,028,614 |
| AbCellera Biologics Inc. (ABCL) |
$259.1m |
1.3% |
33,012,138 |
When they entered and when they scaled
Reported counts below are shares or, for ADR/ADS securities, the reported depositary units. Quarter-end observations locate a change within a quarter, not an execution date.
Seagen Inc. (SGEN)
Entry: July 2003 private financing; first common-stock 13F observation Q3 2004.
Build: 19.32m shares Q2 2013; 27.86m Q4 2014; 37.29m Q4 2015; 43.24m Q2 2016; 45.71m Q4 2016; 51.05m Q2 2018. Thereafter mostly held or trimmed, with 44.55m reported Q3 2023.
The dominant dollar winner. Two principal funds received $10.168bn gross merger consideration for 44,403,909 shares at $229 in December 2023. That is proceeds, not profit. The 13F price-appreciation proxy captures $8.28bn before the final takeover quarter.
Interpretation constraint: Name/CUSIP transition linked; private financing predates public common-stock observation.
Sources: 2004 Q3 13F; 2013 Q2 13F; 2014 Q4 13F; 2015 Q4 13F; 2016 Q2 13F; 2016 Q4 13F; 2018 Q2 13F; 2023 Q3 13F. Additional primary evidence.
The 2003 issuer filing explicitly says Baker Brothers helped lead the July 8 private placement. Seattle Genetics Q2 2003 10-Q.
BeOne Medicines Ltd. (ONC)
Entry: First public ADS 13F observation Q1 2016 as BeiGene (BGNE): 1.913m ADSs. This is not first economic ownership: Baker also held ordinary shares and had board representatives before the IPO.
Reported ADS inventory: 3.673m by Q4 2016; 3.849m Q4 2017; 5.829m Q1 2018; 11.960m Q2 2018. Corrected economic interpretation: January 2018 brought a purchase of 1,980,198 ADSs at $101, approximately $200m. The entire following 6,130,395-ADS increase was conversion of existing ordinary shares without consideration or a change in pecuniary interest. The apparent 3.1x H1 increase was not a tripling of economic exposure. The January purchase increased the two funds' ordinary-share-equivalent holding by approximately 19.8%. Later reported ADS counts: 13.302m Q3 2020; 11.669m Q4 2020; 8.802m Q2 2026. January 2018 purchase; conversion reconciliation.
A major long-term dollar winner. The peak reported position was $4.236bn in Q3 2021. The reported ADS count has been reduced since 2020, while the position remains one of the largest.
Interpretation constraint: BeiGene/BGNE renamed BeOne/ONC; same ADS CUSIP. Counts are ADSs, not the complete ordinary-share economic exposure. Earlier non-ADS ordinary holdings are outside the reported 13F ADS series; the Q2 2018 conversion creates a false accumulation signal.
Sources: 2016 Q1 13F; 2016 Q4 13F; 2018 Q1 13F; 2018 Q2 13F; 2020 Q3 13F; 2020 Q4 13F; 2021 Q3 13F; 2026 Q2 13F.
Revolution Medicines, Inc. (RVMD)
Entry: Q1 2021: 222,222 shares, approximately $10.2m.
Build: 222,222 shares through Q4 2022; 2.691m Q1 2023; 5.149m Q4 2023; 7.549m Q1 2024; 9.365m Q2 2025; 11.443m Q2 2026.
The clearest recent example of a small initial holding followed by a large build. The share count grew about 51.5 times from first observation. The reported position reached $2.143bn and 10.7% in Q2 2026.
Interpretation constraint: Major build began two years after first reported ownership.
Sources: 2021 Q1 13F; 2022 Q4 13F; 2023 Q1 13F; 2023 Q4 13F; 2024 Q1 13F; 2025 Q2 13F; 2026 Q2 13F.
Madrigal Pharmaceuticals, Inc. (MDGL)
Entry: Synta first appears Q2 2012; Madrigal appears Q3 2016 with 57,762 shares after the merger/reverse split.
Build: 57,762 shares through Q3 2017; 615,684 Q4 2017; 1.169m Q2 2018; 1.499m Q1 2020; 1.970m Q4 2023; 2.143m Q2 2026.
The inherited position was initially tiny. The material commitment came in Q4 2017 and Q2 2018, with further additions in 2020 and 2023. The post-merger Q3 2016 quarter-end mark of about $12.67 rose to $536.95 in Q2 2026, a 42.4x stock-price comparison, not the fund's return.
Interpretation constraint: Synta/Madrigal linked with the July 2016 1-for-35 reverse split. Q3 2016 is not a new cash entry.
Sources: 2012 Q2 13F; 2016 Q3 13F; 2017 Q3 13F; 2017 Q4 13F; 2018 Q2 13F; 2020 Q1 13F; 2023 Q4 13F; 2026 Q2 13F. Additional primary evidence.
Celcuity Inc. (CELC)
Entry: Q3 2023: 535,478 shares, approximately $4.9m.
Build: 1.552m Q1 2024; 1.875m Q2 2024; 2.679m Q4 2024; 4.258m Q1 2025; 5.450m Q2 2025; 7.916m Q3 2025, unchanged through Q2 2026.
A rapid multi-quarter build. Much of the share accumulation occurred before the large stock-price increase in H2 2025. Latest reported equity value was $828m; the peak was $904m Q1 2026.
Interpretation constraint: Common-stock analysis excludes separately reported convertible notes and unreported/private instruments. June holdings are not November holdings.
Sources: 2023 Q3 13F; 2024 Q1 13F; 2024 Q2 13F; 2024 Q4 13F; 2025 Q1 13F; 2025 Q2 13F; 2025 Q3 13F; 2026 Q1 13F; 2026 Q2 13F.
Kymera Therapeutics, Inc. (KYMR)
Entry: Q3 2020: 1.959m shares.
Build: 2.385m Q3 2021; 2.880m Q2 2022; 4.375m Q2 2023; 5.996m Q4 2023; 8.657m Q4 2025, unchanged through Q2 2026.
Built through the 2022-23 weak-price period and increased again in 2025. Latest reported stake was $993m and 5.0% of the 13F book.
Interpretation constraint: First public 13F appearance does not establish any earlier private investment date.
Sources: 2020 Q3 13F; 2021 Q3 13F; 2022 Q2 13F; 2023 Q2 13F; 2023 Q4 13F; 2025 Q4 13F; 2026 Q2 13F.
Genomic Health, Inc. (GHDX)
Entry: Q4 2005: 997,402 common shares.
Build: 5.200m by Q4 2008; 8.781m Q4 2011; 13.651m Q2 2013; roughly 13.7m through 2017. Reduced from 13.78m Q3 2018 to 11.74m Q4 2018 and 9.25m Q3 2019.
A long-held winner whose important accumulation predates the ten-year window. Its position peaked near $968m Q3 2018. Exact Sciences acquired it in November 2019 for cash and stock, so its disappearance is not an ordinary open-market exit.
Interpretation constraint: Final cash/stock exchange and subsequent EXAS results are not included in the GHDX appreciation proxy.
Sources: 2005 Q4 13F; 2008 Q4 13F; 2011 Q4 13F; 2013 Q2 13F; 2018 Q3 13F; 2018 Q4 13F; 2019 Q3 13F. Additional primary evidence.
Incyte Corporation (INCY)
Entry: Already owned in the earliest archived quarter, Q4 2001; actual initiation may be earlier.
Build: 14.85m Q4 2014; 19.47m Q3 2015; 23.50m Q1 2016; 34.11m Q1 2017. The Q1 2017 jump largely exchanged $533.5m principal of existing convertible notes for 10.6m shares. Later additions took common shares from 32.02m Q3 2021 to 36.15m Q1 2022. 30.76m shares Q2 2026.
Their largest latest reported holding, $3.487bn/17.5%, and second-largest historical common-stock position by peak dollars. Its importance to the portfolio is much greater than the approximately $550m ten-year common-stock appreciation proxy. Earlier gains and the convertible-bond economics are outside that measure.
Interpretation constraint: Q1 2017 share increase is chiefly a bond exchange, not fresh cash buying.
Sources: 2001 Q4 13F; 2014 Q4 13F; 2015 Q3 13F; 2016 Q1 13F; 2017 Q1 13F; 2021 Q3 13F; 2022 Q1 13F; 2026 Q2 13F. Additional primary evidence.
Rhythm Pharmaceuticals, Inc. (RYTM)
Entry: Q4 2017: 2.049m shares.
Build: 2.708m Q2 2018; after trimming to 2.315m Q4 2020, increased to 3.480m Q1 2021; 6.063m Q3 2022; 6.355m Q4 2022; 5.604m Q2 2026.
Another holding enlarged during a depressed-price period, especially in 2021-22. Latest reported value was $622m, with an approximately $525m appreciation proxy.
Interpretation constraint: Share-count growth and price-driven weight growth are distinct.
Sources: 2017 Q4 13F; 2018 Q2 13F; 2020 Q4 13F; 2021 Q1 13F; 2022 Q3 13F; 2022 Q4 13F; 2026 Q2 13F.
argenx SE (ARGX)
Entry: Q2 2017: 100,000 ADSs.
Build: 962,000 ADSs Q4 2017; 1.020m Q4 2018; 1.120m Q2 2021. Cut to 280,000 Q3 2022, then progressively reduced to 25,000 Q4 2025; absent Q2 2026.
One of the strongest stock-price winners: $21.21 at first reported quarter end to $730.25 at the last reported quarter end, 34.4x. Dollar impact was constrained by the smaller position and substantial selling after 2022. Peak position $424m.
Interpretation constraint: The 34.4x figure is endpoint stock-price appreciation, not realized MOIC. Final exit-quarter gain/loss is unobserved.
Sources: 2017 Q2 13F; 2017 Q4 13F; 2018 Q4 13F; 2021 Q2 13F; 2022 Q3 13F; 2025 Q4 13F; 2026 Q2 13F.
MyoKardia, Inc. (MYOK)
Entry: Q3 2016: 100,000 shares.
Build: 355,000 Q3 2017; 1.016m Q1 2019; 1.517m Q3 2019; 1.774m Q4 2019; 3.164m Q2 2020; 3.009m Q3 2020.
A meaningful takeover winner. BMS paid $225 per share in November 2020 versus the $16.34 first quarter-end mark, a 13.8x stock-price comparison. If all 3.009m last-reported shares were retained to closing, they would produce $677.1m gross cash and approximately $266.8m additional appreciation after Q3. Actual closing holdings were not independently confirmed.
Interpretation constraint: The $245m quarterly appreciation proxy omits the final takeover quarter; a hold-to-close scenario brings it to about $512m, not an audited profit.
Sources: 2016 Q3 13F; 2017 Q3 13F; 2019 Q1 13F; 2019 Q3 13F; 2019 Q4 13F; 2020 Q2 13F; 2020 Q3 13F. Additional primary evidence.
ACADIA Pharmaceuticals Inc. (ACAD)
Entry: First public observation Q1 2005; later rebuilt after intermittent early ownership.
Build: 5.246m Q4 2011; 15.622m Q4 2012; 19.955m Q2 2013; 24.517m Q2 2016; 28.439m Q3 2018; 39.714m Q4 2018; 42.913m Q2 2026.
A very large position, but not one of the biggest price-appreciation winners in this ten-year window. It peaked at $2.240bn Q4 2020 and was $1.086bn in Q2 2026. The common-stock appreciation proxy is negative over the selected window; this does not determine lifetime profit.
Interpretation constraint: Largest modern share-count increase occurred in Q4 2018, about 11.27m shares.
Sources: 2005 Q1 13F; 2011 Q4 13F; 2012 Q4 13F; 2013 Q2 13F; 2016 Q2 13F; 2018 Q3 13F; 2018 Q4 13F; 2020 Q4 13F; 2026 Q2 13F.
Kodiak Sciences Inc. (KOD)
Entry: Q4 2018: 9.145m shares.
Build: 11.047m Q4 2019; 13.880m Q4 2020; 14.681m Q4 2021; 17.310m Q2 2022; 19.919m Q4 2025.
A major peak position, $2.039bn in Q4 2020, but the peak did not represent a realized win. The quarter-end stock mark went from $146.91 Q4 2020 to $3.04 Q4 2023, a 97.9% decline, before recovering to $38.96 Q2 2026. The latest reported stake was $776m.
Interpretation constraint: Do not rank a holding as a successful realized investment just because it once reached a large market value.
Sources: 2018 Q4 13F; 2019 Q4 13F; 2020 Q4 13F; 2021 Q4 13F; 2022 Q2 13F; 2023 Q4 13F; 2025 Q4 13F; 2026 Q2 13F.
Insmed Incorporated (INSM)
Entry: Small positions appear as early as Q3 2004 under a prior CUSIP; current CUSIP first appears Q4 2012.
Build: A 2.156m-share position at Q4 2021 was reduced to 19,950 Q3 2022. Rebuilt to 343,000 Q1 2023; 3.576m Q2 2024; 5.007m Q4 2024; 7.713m Q2 2025. Reduced to 6.593m Q4 2025, then increased to 8.796m Q2 2026.
The relevant modern commitment is the Q2 2024 restart and 2025-26 additions. Latest stake was $938m, below the $1.214bn Q1 2026 peak. It was not a continuously large holding since the first early observation.
Interpretation constraint: Earlier CUSIP history and a near-exit in 2022 matter when interpreting entry dates.
Sources: 2004 Q3 13F; 2012 Q4 13F; 2021 Q4 13F; 2022 Q3 13F; 2023 Q1 13F; 2024 Q2 13F; 2024 Q4 13F; 2025 Q2 13F; 2025 Q4 13F; 2026 Q1 13F; 2026 Q2 13F.
Alexion Pharmaceuticals, Inc. (ALXN)
Entry: First early observation Q4 2002; the modern large holding appears Q2 2015 around the Synageva acquisition.
Build: 6.543m shares Q2 2015; 8.554m Q2 2017; 8.761m Q4 2020; reduced to 3.993m Q1 2021 and absent Q2 2021.
A major historical holding with $1.369bn peak value. The 2015 position followed a cash-and-stock acquisition of Synageva, another Baker investment. Alexion's absence by Q2 2021 predates its later acquisition closing and must not be treated as a held-to-closing exit.
Interpretation constraint: Historical first ownership and the much later major investment episode are different.
Sources: 2002 Q4 13F; 2015 Q2 13F; 2017 Q2 13F; 2020 Q4 13F; 2021 Q1 13F; 2021 Q2 13F. Additional primary evidence.
Praxis Precision Medicines, Inc. (PRAX)
Entry: Q4 2022: 1.830m pre-split shares, approximately 122,021 on the later 1-for-15 basis.
Build: 131,533 split-adjusted shares Q4 2023; 323,105 Q3 2024; 689,488 Q2 2025; 1.126m Q4 2025; 1.753m Q1 2026.
A newer large build, reaching $587m in Q2 2026. The Q1 2024 CUSIP change is not an investment initiation.
Interpretation constraint: November 2023 1-for-15 reverse split adjusted; original share counts retained in ledger.
Sources: 2022 Q4 13F; 2023 Q4 13F; 2024 Q1 13F; 2024 Q3 13F; 2025 Q2 13F; 2025 Q4 13F; 2026 Q1 13F; 2026 Q2 13F. Additional primary evidence.
Other large holdings and material builds
| Investment |
First matched quarter |
Notable changes in the window |
Interpretation |
| BMRN |
2006 Q1 |
2017 Q2: 4.81m to 5.91m; 2017 Q4: 5.91m to 7.58m |
Large additions during 2017; absent after Q3 2023. |
| ABBV |
2015 Q2 |
No qualifying increase in the study window |
Appears Q2 2015 after Pharmacyclics acquisition; no material common-share build in the ten-year window. |
| AMRN |
2015 Q1 |
2016 Q3: 0.80m to 20.63m; 2018 Q3: 22.67m to 34.07m; 2018 Q4: 34.07m to 42.59m |
A large stake with negative captured price appreciation in the window. |
| PRLD |
2020 Q3 |
2020 Q3: 0.00m to 10.12m (first/reappearance) |
First observed Q3 2020 with 10.12m shares; peak size was not preserved. |
| ASND |
2015 Q1 |
2017 Q2: 1.35m to 1.75m; 2017 Q3: 1.75m to 2.35m; 2021 Q3: 3.54m to 4.54m |
Material builds in 2017 and Q3 2021; last observed Q4 2022. |
| SMMT |
2022 Q4 |
2024 Q2: 0.00m to 23.22m (first/reappearance); 2025 Q2: 24.42m to 33.72m |
Absent Q4 2023/Q1 2024; reappeared Q2 2024. This is not a continuous-share comparison. |
| NVTA |
2015 Q1 |
2019 Q3: 3.90m to 8.79m; 2020 Q2: 9.10m to 11.85m; 2020 Q4: 11.85m to 15.65m |
Large 2019–20 increases, followed by a severe loss of reported value. |
| ABCL |
2020 Q4 |
2020 Q4: 0.00m to 10.45m (first/reappearance); 2023 Q2: 10.45m to 16.45m; 2024 Q1: 22.91m to 27.53m |
Share count increased repeatedly while the stock declined from its initial public-period mark. |
The workbook retains all underlying quarters and sources for these changes; the source-linked Scaling table includes material first appearances and reappearances as well as increases in continuing holdings.
Percentage winners and selection effects
For large or economically meaningful examples, argenx rose from the first reported quarter-end mark of $21.21 to the last reported mark of $730.25 (34.4x); Madrigal rose from its first post-merger mark of $12.67 to $536.95 (42.4x); Celcuity rose from $9.14 to $104.62 (11.4x); and MyoKardia’s $225 takeout price was 13.8x the $16.34 first reported mark. These are stock-price comparisons across the specified dates, not Baker’s money-weighted returns. Argenx was heavily trimmed along the way; Madrigal was an inherited Synta position before it was enlarged. The share timelines and primary sources above establish the endpoints.
A broad stock-price screen also finds Krystal Biotech, Arrowhead, Array, Merus, Mirum and ChemoCentryx among high-multiple price histories, but their peak Baker positions were much smaller. The long-tail screen is not a corporate-action-complete percentage-return leaderboard, so I do not treat endpoint ratios as fund performance or rank them as such.
What the history suggests
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Small initial positions often preceded the real commitment by years. Revolution held at 222,222 shares from Q1 2021 through Q4 2022, then expanded to 7.55m by Q1 2024. Madrigal stayed around 57,762 shares until Q4 2017.
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The share-count inflection requires transaction reconciliation. Revolution’s 2023–24 build, Celcuity’s 2024–25 build and Insmed’s Q2 2024 restart merit study. BeiGene's genuine January 2018 financing participation is also useful, but its much larger Q2 ADS increase was conversion of previously owned ordinary shares, not new buying.
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Large price gains can create concentration without buying. Seagen grew from a roughly $1.75bn holding in Q2 2016 to a $9.50bn peak in Q1 2023 while its share count changed far less. By Q3 2023 it represented 54.5% of the reported book.
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Size alone is a poor definition of a winner. Acadia, Kodiak, Prelude and Invitae reached major position sizes. Their later paths differed sharply from the persistent dollar winners. Kodiak’s quarter-end price fell 97.9% between Q4 2020 and Q4 2023 while the reported share count grew.
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Corporate actions can masquerade as conviction buying. Incyte’s Q1 2017 share increase was predominantly a debt exchange; Madrigal’s first entry was a reverse merger; Alexion and AbbVie inherited economic exposure from earlier takeovers.
Scope exclusions and remaining uncertainty
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Pharmacyclics and Synageva: famous Baker successes, but their acquisition closings in May and June 2015 precede this ten-year window. Including those proceeds would silently change the requested period. Pharmacyclics was already a $2.314bn position in Q1 2015; Synageva was $1.137bn. The later AbbVie and Alexion holdings remain in the study. 2015 Q1 13F; AbbVie closing announcement; Synageva closing disclosure.
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Public information only: private positions, unlisted holdings, short positions and confidentially omitted holdings are not an exhaustive part of the 13F record. A first public appearance may follow an earlier private investment.
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Not actual P&L: all trade timing, cost basis and realized/unrealized splits remain unknown. In-kind distributions and conversions can change reported shares without purchases or sales. The proxy’s use of average quarterly inventories is a transparent approximation.
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Exit-quarter bias: full exits are absent from the next 13F; their final-quarter gain/loss cannot be calculated from these tables alone. I discuss Seagen and MyoKardia separately. Genomic Health’s cash-and-stock exit and subsequent Exact Sciences investment are not joined into a single profit estimate.
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Security continuity: selected material corporate actions were verified and linked. Other CUSIP changes remain separate, and six possible split/ADS-change intervals were excluded from the proxy. The raw ledger remains complete.
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Dates and denominations: first matched dates are observation dates, not first purchases. Depositary units are not underlying ordinary shares. Portfolio weights are fractions of reported 13F value, not total investment-fund assets.
Deliverables
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Full workbook: summary, 408 equity security histories, material scaling events, transparent appreciation formulas, every original holding in the study plus baseline, and filing controls.
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Share-count timeline.
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Source archive and reproducible calculations: local research archive; public references are listed under Sources & files.