The Observatory
Curated prominent managers — concentrated value investors, activists, quants and the passive giants — observed quarter by quarter.
Filings belong to firms, not individuals — we write “Berkshire Hathaway reported…”, never “Buffett bought…”. Each entry notes the associated person and what kind of book the 13F reveals.
World's largest asset manager — Mostly passive/ETF assets — read size, not conviction.
49,968 positions · top-10 28.1% · +237 new · −183 exits
SPDR ETF sponsor — Passive giant; index flows dominate changes.
4,261 positions · top-10 29.0% · +98 new · −96 exits
Fidelity Investments' manager — Active + index fund complex.
13,978 positions · top-10 34.0% · +335 new · −195 exits
Bank/wealth platform — Bank-affiliated adviser aggregating client assets.
45,905 positions · top-10 21.1% · +423 new · −268 exits
Manages Fidelity index funds — Passive manager for Fidelity-branded index funds.
8,470 positions · top-10 31.1% · +128 new · −165 exits
Bank asset & wealth management — Bank-affiliated manager; broad book.
34,064 positions · top-10 26.3% · +573 new · −279 exits
Bank asset & wealth management — Bank-affiliated manager; broad book.
14,070 positions · top-10 22.6% · +572 new · −461 exits
Norway's sovereign wealth fund (NBIM) — The world's largest sovereign equity owner; near-index breadth.
1,617 positions · top-10 32.4% · +1602 new
Active fund complex — Large active growth manager.
4,722 positions · top-10 32.3% · +219 new · −114 exits
Ken Griffin (Founder & CEO) — Multi-strategy platform; heavy reported options activity — read positions with care.
16,122 positions · top-10 16.0% · +1585 new · −1241 exits
Capital Group division — American Funds' long-only equity.
637 positions · top-10 29.6% · +65 new · −55 exits
Institutional asset manager — One of the largest active institutional managers.
7,448 positions · top-10 25.0% · +214 new · −159 exits
Ken Fisher (Founder) — Large RIA managing many separate accounts — breadth over conviction.
1,037 positions · top-10 35.6% · +122 new · −96 exits
Warren Buffett (Chairman & CEO) — The holding company's reported U.S. equity book; famously concentrated and long-held.
89 positions · top-10 88.5% · +1 new · −1 exits
Cliff Asness (Co-founder) — Systematic factor investing across thousands of names.
21,077 positions · top-10 12.2% · +244 new · −81 exits
Izzy Englander (Founder) — Multi-manager pod platform; aggregate positions reflect many independent teams.
5,798 positions · top-10 19.4% · +550 new · −588 exits
Quantitative institutional manager — Systematic global equity.
1,887 positions · top-10 27.7% · +373 new · −299 exits
Founded by David E. Shaw — Quantitative multi-strategy manager.
6,298 positions · top-10 20.2% · +543 new · −289 exits
Value mutual-fund manager — Long-only value funds; positions turn over slowly.
222 positions · top-10 27.9% · +7 new · −6 exits
Sub-adviser to Vanguard funds — Long-duration growth positions.
324 positions · top-10 42.5% · +10 new · −6 exits
Founded by John Overdeck & David Siegel — Quantitative manager; broad, fast-turning book.
5,017 positions · top-10 8.4% · +607 new · −372 exits
London long/short platform — Systematic + discretionary long/short.
6,550 positions · top-10 40.5% · +667 new · −625 exits
Edinburgh growth manager — Long-horizon growth investing.
880 positions · top-10 44.7% · +28 new · −24 exits
Steve Cohen (Founder) — Multi-manager platform with discretionary pods.
3,923 positions · top-10 14.8% · +625 new · −611 exits
Manager of the Oakmark funds — Long-only value funds.
226 positions · top-10 31.5% · +12 new · −7 exits
Founded by Jim Simons — Quantitative manager holding thousands of positions; single names carry little signal.
3,140 positions · top-10 12.0% · +546 new · −604 exits
Manages Harvard-lineage capital — Low-profile, benchmark-aware stock picking.
1,002 positions · top-10 29.5% · +147 new · −112 exits
Chris Hohn (Founder) — Very concentrated, long-duration positions.
11 positions · top-10 98.6% · +2 new · −1 exits
Philippe Laffont (Founder) — Technology-focused crossover manager.
211 positions · top-10 61.9% · +9 new · −5 exits
Joel Greenblatt (Co-CIO) — Systematic value; hundreds of small long positions.
1,791 positions · top-10 28.4% · +174 new · −128 exits
Founded by Andreas Halvorsen — Fundamental long/short equity.
90 positions · top-10 35.7% · +33 new · −21 exits
Endowment trust — Concentrated endowment portfolio.
24 positions · top-10 94.9% · +2 new
Founded by Ray Dalio — One of the largest macro managers; the 13F shows only its reportable U.S. long book.
997 positions · top-10 40.0% · +212 new · −208 exits
Chase Coleman (Founder) — Growth/technology crossover investing.
46 positions · top-10 67.1% · +9 new · −16 exits
Paul Singer (Founder) — Activist positions often paired with derivatives that 13Fs only partially reveal.
29 positions · top-10 95.6% · +2 new · −2 exits
Founded by Stephen Mandel — Growth-oriented long/short equity.
34 positions · top-10 53.9% · +13 new · −15 exits
Cathie Wood (CEO) — Thematic ETF manager — its 13F largely mirrors its funds' disclosed holdings.
191 positions · top-10 39.5% · +15 new · −6 exits
Insurance holding company — Buffett-style equity book inside an insurer.
205 positions · top-10 42.9% · +3 new · −2 exits
Mario Gabelli (Chairman) — Value manager with many small-cap holdings.
938 positions · top-10 15.4% · +35 new · −98 exits
Brad Gerstner (Founder) — Technology-focused crossover manager.
20 positions · top-10 83.3% · +9 new · −2 exits
Carl Icahn — Activist positions, often alongside 13D filings.
18 positions · top-10 98.6%
Family office of George Soros — Macro-driven family office.
266 positions · top-10 29.4% · +85 new · −78 exits
David Tepper (President) — Opportunistic, macro-aware equity positioning.
27 positions · top-10 81.6% · +6 new · −12 exits
Co-founded by Howard Marks — Credit specialist; the 13F shows only its listed-equity sliver.
145 positions · top-10 66.5% · +8 new · −11 exits
Founded by Jeff Ubben; led by Mason Morfit — Constructive activist with board seats.
18 positions · top-10 88.2% · +1 new · −1 exits
Larry Robbins (CEO) — Healthcare-heavy fundamental manager.
45 positions · top-10 64.1% · +12 new · −11 exits
Seth Klarman (CEO) — Value investor; much of the portfolio (cash, credit, private) never appears in a 13F.
23 positions · top-10 74.9% · +3 new · −2 exits
Stanley Druckenmiller (Chairman) — Macro-aware equity family office.
95 positions · top-10 52.4% · +44 new · −23 exits
Daniel Loeb (CEO) — Event-driven and activist equity manager.
43 positions · top-10 60.6% · +16 new · −9 exits
Jeff Smith (CEO) — Activist campaigns in mid-cap companies.
22 positions · top-10 84.3% · +2 new · −4 exits
Nelson Peltz (CEO) — Concentrated operational activism.
9 positions · top-10 100.0%
David Einhorn (President) — Long/short value manager (adviser entity renamed DME Capital Management) — 13F shows reportable longs only.
95 positions · top-10 52.8% · +7 new · −6 exits
Li Lu (Founder) — Very concentrated value book.
8 positions · top-10 100.0% · −6 exits
Prem Watsa (Chairman) — Insurance holding company's equity portfolio.
32 positions · top-10 90.8% · +6 new · −3 exits
Classic Graham-and-Dodd firm — Old-school value manager.
91 positions · top-10 69.2% · +13 new · −15 exits
Mohnish Pabrai (Managing Partner) — Ultra-concentrated value vehicle.
4 positions · top-10 100.0% · +1 new
Bill Ackman (CEO) — Concentrated activist positions in a small number of large companies.
holdings parsing in progress
Michael Burry (Founder) — Small, concentrated book; reported options make headline positions easy to misread.
holdings parsing in progress
Index-fund pioneer — Passive giant — position changes mostly reflect index flows, not views.
holdings parsing in progress