Arkolith/Funds/Baker Bros. Advisors LP

Baker Bros. Advisors LP

CIK 1263508
Holdings as of Mar 31, 2026·disclosed May 15, 2026·~45-day 13F lag·13F-HR
Active Filer

Baker Bros. Advisors LP holds a focused book of 84 stocks worth $17.4B as of Q1 2026 (disclosed May 15, 2026, a ~45-day 13F lag). This quarter they opened Mirum Pharmaceuticals Inc and trimmed Roivant Sciences Ltd. Their largest long position is Incyte Corp at 17% of the equity book.

Build

Build on this 13F portfolio

The public view is the crawlable proof. The same sourced dataset is available through REST and MCP for agents, research scripts, and back-office tools.

13F holdings API

Owners, holdings, deltas, point-in-time portfolios.

stock.owners

Form 4 insider API

Open-market buys and sells, cluster scans, company flows.

insider.transactions

MCP quickstart

Connect an agent, mint a key, make the first call.

/api/mcp
Build

Ask your agent what Baker Bros. Advisors LP owns

This fund page is the Follow view. The Build view lets your agent pull holdings, quarter changes, overlap, and source filings through API or MCP.

Get a key Compare plans13F data
Copy-paste
curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://arkolith.com/api/v1/funds/1263508/holdings"
Ask your agent
Use Arkolith to show BAKER BROS. ADVISORS LP's latest
holdings, largest changes, and filing provenance.
Opened
7
new positions
Added to
18
existing
Trimmed
6
reduced
Sold out
9
exited

Concentration

Top-heavy: focused book

Top 5 holdings
51%
Top 10 holdings
73%
Top 20 holdings
88%

Share of the disclosed book in its largest positions. A higher top-5 share means a more concentrated, higher-conviction portfolio.

Direct sector allocation

100% mapped to company sectors

Health Care
100%
ETF / fund or unclassified
0%

Direct operating-company sectors from our SIC-based security master. ETF/fund and unclassified holdings stay visible separately; this is not ETF look-through exposure.

Biggest moves: latest quarter

Estimated $ traded · quarter-end prices, no cost basis

Bought
Trimmed / exited

Holdings: largest first

Bars show each stock's share of the portfolio. Click a row for its position history.

84 positions
#SecurityValueShares% PortLast moveHistory
1Incyte Corporation
COM
$2.9B30.74M
16.6%
▲~0%
Added · +421 sh
2BeOne Medicines Ltd.
SPONSORED ADS
$2.6B8.80M
15.0%
—Held
3Insmed Incorporated
COM PAR $.01
$1.2B7.42M
7.0%
▲+13%
Added · +828K sh
4Madrigal Pharmaceuticals, Inc.
COM
$1.1B2.14M
6.4%
—Held
5ACADIA Pharmaceuticals Inc.
COM
$954.9M42.90M
5.5%
—Held
6Revolution Medicines, Inc.
COM
$929.3M9.56M
5.3%
▲+1.1%
Added · +100K sh
7Celcuity Inc.
COM
$903.5M7.92M
5.2%
—Held
8Kodiak Sciences Inc.
COM
$759.3M19.92M
4.4%
—Held
9Kymera Therapeutics, Inc.
COM
$721.1M8.66M
4.1%
—Held
10Summit Therapeutics Inc.
COM
$690.0M36.39M
4.0%
—Held
11Praxis Precision Medicines, Inc.
COM
$564.9M1.75M
3.2%
▲+56%
Added · +627K sh
12Rhythm Pharmaceuticals, Inc.
COM
$487.4M5.60M
2.8%
—Held
13Alkermes plc
SHS
$354.0M10.01M
2.0%
—Held
14Grail, Inc.
COM
$208.2M4.03M
1.2%
▲+93%
Added · +1.9M sh
15Edgewise Therapeutics, Inc.
COM
$207.1M6.58M
1.2%
—Held
16Ionis Pharmaceuticals, Inc.
COM
$153.8M2.05M
0.9%
▲+14%
Added · +256K sh
17Kiniksa Pharmaceuticals International, plc
ORD SHS CL A
$136.1M2.83M
0.8%
—Held
18Immunovant, Inc.
COM
$135.6M5.46M
0.8%
—Held
19Roivant Sciences Ltd.
SHS
$134.8M4.87M
0.8%
▼−12%
Reduced · −687K sh
20IDEAYA Biosciences, Inc.
COM
$131.5M3.95M
0.8%
▲+9.1%
Added · +328K sh
21Arrowhead Pharmaceuticals, Inc.
COM
$124.9M1.99M
0.7%
▼−8.4%
Reduced · −183K sh
22Stoke Therapeutics, Inc.
COM
$108.6M3.34M
0.6%
—Held
23Immatics N.V.
SHS
$107.4M10.92M
0.6%
▼−9.7%
Reduced · −1.2M sh
24AbCellera Biologics Inc.
COM
$105.7M30.28M
0.6%
▲+10.0%
Added · +2.8M sh
25Abivax S.A.
SPONSORED ADS
$97.5M875.8K
0.6%
—Held
26Crinetics Pharmaceuticals, Inc.
COM
$85.4M2.35M
0.5%
▲+43%
Added · +703K sh
27Replimune Group, Inc.
COM
$84.5M11.05M
0.5%
—Held
28Celcuity Inc.
Note 2.75% 8/1/2031
$74.9M30.75M
0.4%
—Held
29Nurix Therapeutics, Inc.
COM
$72.2M4.66M
0.4%
—Held
30Denali Therapeutics Inc.
COM
$71.6M3.73M
0.4%
—Held
31Dianthus Therapeutics, Inc.
COM
$71.5M852.2K
0.4%
▲+7.9%
Added · +62K sh
32Monte Rosa Therapeutics, Inc.
COM
$71.5M4.35M
0.4%
—Held
33Structure Therapeutics Inc.
SPONSORED ADS
$69.0M1.43M
0.4%
—Held
34Entrada Therapeutics, Inc.
COM
$64.0M5.07M
0.4%
—Held
35Bicycle Therapeutics plc
SPONSORED ADS
$50.5M10.89M
0.3%
—Held
36Spyre Therapeutics, Inc.
COM
$50.4M1.00M
0.3%
—Held
37Rapport Therapeutics, Inc.
COM
$48.4M1.55M
0.3%
—Held
38Alumis Inc.
COM
$44.3M2.01M
0.3%
▲+29%
Added · +450K sh
39Mirum Pharmaceuticals, Inc.
COM
$41.2M446.0K
0.2%
▲New
New position
40Viridian Therapeutics, Inc.
COM
$38.6M1.97M
0.2%
—Held
41Enliven Therapeutics, Inc.
COM
$35.5M905.2K
0.2%
▲+234%
Added · +634K sh
42Prelude Therapeutics Inc.
COM
$34.6M10.12M
0.2%
—Held
43DBV Technologies S.A.
SPONSORED ADS
$30.5M1.46M
0.2%
—Held
44Design Therapeutics, Inc.
COM
$27.5M2.59M
0.2%
▲+16%
Added · +353K sh
45Centessa Pharmaceuticals plc
SPONSORED ADS
$26.6M670.8K
0.2%
—Held
46CytomX Therapeutics, Inc.
COM
$23.4M4.98M
0.1%
▲+17%
Added · +725K sh
47Jade Biosciences, Inc.
COM
$23.1M1.64M
0.1%
—Held
48Disc Medicine, Inc.
COM
$22.4M349.7K
0.1%
▲+3.7%
Added · +13K sh
49Immunocore Holdings plc
ADS
$22.1M734.4K
0.1%
▼−68%
Reduced · −1.6M sh
50Xenon Pharmaceuticals Inc.
COM
$21.5M370.2K
0.1%
—Held
Showing 50 of 84 positions

Filing history

As-of date vs the date the SEC received each filing

QuarterAs ofFiledPositionsValueForm
Q1 2026Mar 31, 2026May 15, 202684$17.4B13F-HR
Q4 2025Dec 31, 2025Feb 17, 202686$17.1B13F-HR
Q3 2025Sep 30, 2025Nov 14, 202591$13.8B13F-HR
Q2 2025Jun 30, 2025Aug 14, 202589$10.3B13F-HR
Q1 2025Mar 31, 2025May 15, 202589$9.0B13F-HR
Q4 2024Dec 31, 2024Feb 14, 202595$9.4B13F-HR
Q3 2024Sep 30, 2024Nov 14, 202493$9.6B13F-HR
Q2 2024Jun 30, 2024Aug 14, 202495$7.8B13F-HR
Q1 2024Mar 31, 2024May 15, 202487$8.0B13F-HR
Q4 2023Dec 31, 2023Feb 14, 202484$8.8B13F-HR
Q3 2023Sep 30, 2023Nov 14, 2023101$17.4B13F-HR
Q2 2023Jun 30, 2023Aug 14, 2023107$17.3B13F-HR
Q1 2023Mar 31, 2023May 15, 2023105$18.4B13F-HR
Q4 2022Dec 31, 2022Feb 14, 2023113$16.7B13F-HR
Q3 2022Sep 30, 2022Nov 14, 2022115$15.3B13F-HR
Q2 2022Jun 30, 2022Aug 15, 2022117$17.6B13F-HR
Q1 2022Mar 31, 2022May 16, 2022118$17.4B13F-HR
Q4 2021Dec 31, 2021Feb 14, 2022121$20.6B13F-HR
Q3 2021Sep 30, 2021Nov 15, 2021122$22.8B13F-HR
Q2 2021Jun 30, 2021Aug 16, 2021120$22.8B13F-HR
Q1 2021Mar 31, 2021May 17, 2021126$23.1B13F-HR
Q4 2020Dec 31, 2020Feb 16, 2021126$26.5B13F-HR
Q3 2020Sep 30, 2020Nov 16, 2020120$25.0B13F-HR
Q2 2020Jun 30, 2020Aug 14, 2020114$22.7B13F-HR

Data source

Holdings from SEC EDGAR 13F-HR filings, updated quarterly ~45 days after quarter-end. Public domain. The book and weighting are long equity only; disclosed put/call options are listed separately and excluded from those totals. Price-derived performance is withheld until the price-source policy and freshness gate are green.