Vault-13

ARCELLX INC ACLX

COMMON STOCK · Common Stock · CUSIP 03940C100

240 institutional holders +21 vs Q4 2025
56,924,27356.9m shares reported held*
$6.5bnreported value*
84 new 62 added 56 reduced 71 sold out net sold ≈ $2.0bn (-17.5m shares)

* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once ($8.5m this quarter). Holder counts are more reliable. Implied quarter-end price ≈ $114.30. Options: 16 managers hold calls ($128.0m notional), 17 hold puts ($45.1m).

Trends to Q1 2026

Institutional holders

Managers reporting a position, each quarter

0100200300Q3 22: 74Q4 22: 127Q1 23: 119Q2 23: 140Q3 23: 138Q4 23: 158Q1 24: 184Q2 24: 168Q3 24: 187Q4 24: 213Q1 25: 200Q2 25: 205Q3 25: 210Q4 25: 219Q1 26: 240240Q3 22Q3 23Q3 24Q3 25Q1 26
Numbers
QuarterHolders
Q3 202274
Q4 2022127
Q1 2023119
Q2 2023140
Q3 2023138
Q4 2023158
Q1 2024184
Q2 2024168
Q3 2024187
Q4 2024213
Q1 2025200
Q2 2025205
Q3 2025210
Q4 2025219
Q1 2026240

Buyers vs sellers

Managers adding to or starting a position, vs cutting or selling out

Bought or addedCut or sold out
2000200Q2 24: 99 bought or addedQ2 24: 86 cut or sold outQ3 24: 102 bought or addedQ3 24: 79 cut or sold outQ3 24Q4 24: 112 bought or addedQ4 24: 79 cut or sold outQ1 25: 97 bought or addedQ1 25: 107 cut or sold outQ1 25Q2 25: 90 bought or addedQ2 25: 106 cut or sold outQ3 25: 87 bought or addedQ3 25: 101 cut or sold outQ3 25Q4 25: 108 bought or addedQ4 25: 102 cut or sold outQ1 26: 146 bought or addedQ1 26: 127 cut or sold outQ1 26
Numbers
QuarterBought or addedCut or sold out
Q2 20249986
Q3 202410279
Q4 202411279
Q1 202597107
Q2 202590106
Q3 202587101
Q4 2025108102
Q1 2026146127

Calls vs puts

Options held, notional value, last 4 quarters. P/C = puts ÷ calls

CallsPuts
$0$50m$100m$150mQ2 25 calls: $18.7mQ2 25 puts: $58.5mQ2 25P/C 3.13Q3 25 calls: $7.5mQ3 25 puts: $9.6mQ3 25P/C 1.29Q4 25 calls: $21.8mQ4 25 puts: $16.4mQ4 25P/C 0.75Q1 26 calls: $128.0mQ1 26 puts: $45.1mQ1 26P/C 0.35
Numbers
QuarterCallsPutsP/C
Q2 2025$18.7m$58.5m3.13
Q3 2025$7.5m$9.6m1.29
Q4 2025$21.8m$16.4m0.75
Q1 2026$128.0m$45.1m0.35

Biggest buyers

Pentwater Capital Management LP New +2,870,000+2.9m
FIL Ltd New +2,339,192+2.3m
HBK INVESTMENTS L P New +2,278,517+2.3m
GLAZER CAPITAL, LLC New +1,507,128+1.5m
GOLDMAN SACHS GROUP INC Added +643,675+643.7k
TIG Advisors, LLC New +541,378+541.4k
ALLIANCEBERNSTEIN L.P. Added +503,436+503.4k
MILLENNIUM MANAGEMENT LLC Added +494,025+494.0k
Balyasny Asset Management L.P. New +479,763+479.8k
TUDOR INVESTMENT CORP ET AL Added +416,559+416.6k

Biggest sellers

T. Rowe Price Investment Management, Inc. Reduced -13,958,070-14.0m
FMR LLC Reduced -3,444,350-3.4m
Vestal Point Capital, LP Sold out -2,925,000-2.9m
PRICE T ROWE ASSOCIATES INC /MD/ Reduced -1,564,847-1.6m
CITADEL ADVISORS LLC Reduced -1,478,417-1.5m
PERCEPTIVE ADVISORS LLC Sold out -1,466,071-1.5m
RA CAPITAL MANAGEMENT, L.P. Sold out -1,267,156-1.3m
JPMORGAN CHASE & CO Reduced -860,904-860.9k
JANUS HENDERSON GROUP PLC Reduced -829,298-829.3k
Woodline Partners LP Reduced -614,074-614.1k

Biggest calls

SUSQUEHANNA INTERNATIONAL GROUP, LLP Added $58.3m508.0k shares
Caption Management, LLC Reduced $25.8m225.0k shares
EQUITEC PROPRIETARY MARKETS, LLC New $23.6m205.3k shares
SIMPLEX TRADING, LLC Added $4.7m41.1k shares
GOLDMAN SACHS GROUP INC Added $2.9m25.0k shares
NOMURA HOLDINGS INC New $2.8m24.7k shares
JANE STREET GROUP, LLC Added $2.6m23.0k shares
JPMORGAN CHASE & CO Unchanged $2.3m20.0k shares
UBS Group AG New $1.4m12.3k shares
CITADEL ADVISORS LLC Added $1.2m10.8k shares

Biggest puts

PICTON MAHONEY ASSET MANAGEMENT New $8.6m75.0k shares
EQUITEC PROPRIETARY MARKETS, LLC New $5.5m48.2k shares
SUSQUEHANNA INTERNATIONAL GROUP, LLP Added $5.2m44.9k shares
SIMPLEX TRADING, LLC Reduced $4.5m39.4k shares
JANE STREET GROUP, LLC Reduced $3.5m30.8k shares
GOLDMAN SACHS GROUP INC Added $3.2m28.0k shares
Caption Management, LLC Reduced $2.9m25.0k shares
NOMURA HOLDINGS INC New $2.8m24.7k shares
CITADEL ADVISORS LLC Reduced $2.3m20.1k shares
JPMORGAN CHASE & CO Unchanged $2.3m20.0k shares

Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.

Major shareholders (over 5%)

Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.

HolderStakeChangeShares Last filed
GILEAD SCIENCES, INC. 13D · may seek influence +88.5 pts · filed 2026-04-28
Stated purposeItem 4 of the Original Schedule 13D is amended to include the following at the end thereof: "As previously disclosed, Gilead, Purchaser and Arcellx entered into the Merger Agreement pursuant to which Purchaser commenced the Offer on March 6, 2026. The Offer expired at 5:00 p.m., Eastern Time, on April 27, 2026. Computershare Trust Company N.A., the depositary and paying agent for the Offer, advised Gilead that, as of the expiration of the Offer, 38,795,604 Shares had been validly tendered and not validly withdrawn pursuant to the Offer, representing, together with Shares already owned by Gilead, approximately 77.2% of the Shares outstanding as of the expiration of the Offer. Following consummation of the Offer, on April 28, 2026, Gilead completed its acquisition of Arcellx through the m… Full filing
 100.0% +88.5 pts 100 2026-04-28
BlackRock, Inc. 13G · institution filed 2025-04-17 6.4% 3.5m 2025-04-17

Fell to 5% or below in the last year: Paradigm Biocapital Advisors LP (0.0%, 2026-08-14), Vestal Point Capital, LP (0.0%, 2026-05-15), New Enterprise Associates 15, L.P. (0.0%, 2026-04-30), Elghandour Rami (0.0%, 2026-04-28), VANGUARD GROUP INC (0.0%, 2026-03-26), T. Rowe Price Investment Management, Inc. (4.5%, 2026-03-06), FMR LLC (0.5%, 2026-03-06), RA CAPITAL MANAGEMENT, L.P. (2.2%, 2026-02-17)

Holders, Q1 2026

#ManagerLocationShares Value% of their portfolioChangeShares change
1 GILEAD SCIENCES, INC. 36.44% of their portfolio FOSTER CITY, CA 6,720,8036.7m $771.7m $771.7m 36.44% Unchanged
2 Paradigm Biocapital Advisors LP 13.55% of their portfolio NEW YORK, NY 5,774,0165.8m $663.0m $663.0m 13.55% Added +50.0k +50,000
3 BlackRock, Inc. 0.01% of their portfolio New York, NY 3,945,2383.9m $453.0m $453.0m 0.01% Added +396.5k +396,451
4 NEA Management Company, LLC 19.88% of their portfolio TIMONIUM, MD 3,045,2623.0m $349.7m $349.7m 19.88% Unchanged
5 Pentwater Capital Management LP 2.34% of their portfolio Naples, FL 2,870,0002.9m $329.5m $329.5m 2.34% New
6 VANGUARD CAPITAL MANAGEMENT LLC 0.01% of their portfolio MALVERN, PA 2,425,2182.4m $278.5m $278.5m 0.01% First filing
7 VANGUARD PORTFOLIO MANAGEMENT LLC 0.01% of their portfolio MALVERN, PA 2,424,8182.4m $278.4m $278.4m 0.01% First filing
8 SR One Capital Management, LP 29.43% of their portfolio Redwood City, CA 2,346,6302.3m $269.4m $269.4m 29.43% Unchanged
9 FIL Ltd 0.21% of their portfolio HAMILTON, D0 2,339,1922.3m $268.6m $268.6m 0.21% New
10 HBK INVESTMENTS L P 3.29% of their portfolio DALLAS, TX 2,278,5172.3m $261.6m $261.6m 3.29% New
11 T. Rowe Price Investment Management, Inc. 0.18% of their portfolio BALTIMORE, MD 2,255,8782.3m $259.0m $259.0m 0.18% Reduced -14.0m -13,958,070
12 STATE STREET CORP 0.01% of their portfolio BOSTON, MA 1,675,8951.7m $192.4m $192.4m 0.01% Reduced -322.6k -322,608
13 GLAZER CAPITAL, LLC 3.68% of their portfolio New York, NY 1,507,1281.5m $173.0m $173.0m 3.68% New
14 GOLDMAN SACHS GROUP INC 0.02% of their portfolio NEW YORK, NY 1,312,1551.3m $150.7m $150.7m 0.02% Added +643.7k +643,675
15 GEODE CAPITAL MANAGEMENT, LLC 0.01% of their portfolio BOSTON, MA 1,028,6661.0m $118.1m $118.1m 0.01% Added +70.6k +70,609
16 MORGAN STANLEY 0.01% of their portfolio NEW YORK, NY 925,813925.8k $106.3m $106.3m 0.01% Added +407.4k +407,409
17 JPMORGAN CHASE & CO 0.00% of their portfolio NEW YORK, NY 593,573593.6k $68.1m $68.1m 0.00% Reduced -860.9k -860,904
18 Davidson Kempner Capital Management LP 1.14% of their portfolio New York, NY 559,644559.6k $64.3m $64.3m 1.14% Not comparable
19 ALLIANCEBERNSTEIN L.P. 0.01% of their portfolio NASHVILLE, TN 544,227544.2k $35.5m $35.5m 0.01% Added +503.4k +503,436
20 TIG Advisors, LLC 2.97% of their portfolio New York, NY 541,378541.4k $62.2m $62.2m 2.97% New
21 MILLENNIUM MANAGEMENT LLC 0.04% of their portfolio NEW YORK, NY 502,846502.8k $57.7m $57.7m 0.04% Added +494.0k +494,025
22 Balyasny Asset Management L.P. 0.11% of their portfolio Chicago, IL 479,763479.8k $55.1m $55.1m 0.11% New
23 TUDOR INVESTMENT CORP ET AL 0.29% of their portfolio STAMFORD, CT 462,588462.6k $53.1m $53.1m 0.29% Added +416.6k +416,559
24 BANK OF AMERICA CORP /DE/ 0.00% of their portfolio CHARLOTTE, NC 452,333452.3k $51.9m $51.9m 0.00% Added +24.6k +24,564
25 O'Connor Alternative Investments LLC 2.71% of their portfolio NEW YORK, NY 450,504450.5k $51.7m $51.7m 2.71% First filing
26 Magnetar Financial LLC 0.46% of their portfolio EVANSTON, IL 394,931394.9k $45.3m $45.3m 0.46% New
27 ALPINE ASSOCIATES MANAGEMENT INC. 2.56% of their portfolio PALM BEACH, FL 378,000378.0k $43.4m $43.4m 2.56% New
28 NEXPOINT ASSET MANAGEMENT, L.P. 2.99% of their portfolio Dallas, TX 373,150373.1k $42.8m $42.8m 2.99% New
29 Affinity Asset Advisors, LLC 2.44% of their portfolio NEW YORK, NY 362,764362.8k $41.7m $41.7m 2.44% Reduced -161.0k -160,961
30 NORTHERN TRUST CORP 0.01% of their portfolio CHICAGO, IL 350,065350.1k $40.2m $40.2m 0.01% Added +28.3k +28,272
31 CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.01% of their portfolio SAN FRANCISCO, CA 346,092346.1k $39.7m $39.7m 0.01% Added +6.3k +6,279
32 VANGUARD FIDUCIARY TRUST CO 0.01% of their portfolio MALVERN, PA 308,546308.5k $35.4m $35.4m 0.01% First filing
33 Qube Research & Technologies Ltd 0.05% of their portfolio LONDON, X0 303,847303.8k $34.9m $34.9m 0.05% Added +205.9k +205,941
34 First Trust Capital Management L.P. 1.44% of their portfolio CHICAGO, IL 238,235238.2k $27.4m $27.4m 1.44% New
35 AQR Arbitrage LLC 0.44% of their portfolio Greenwich, CT 231,730231.7k $26.6m $26.6m 0.44% New
36 AJU IB Investment Co., Ltd. 84.07% of their portfolio Seoul, M5 223,486223.5k $25.7m $25.7m 84.07% Unchanged
37 LMR Partners LLP 0.22% of their portfolio LONDON, X0 212,495212.5k $24.4m $24.4m 0.22% New
38 BARCLAYS PLC 0.01% of their portfolio LONDON, X0 207,642207.6k $23.8m $23.8m 0.01% Added +10.9k +10,870
39 SOROS FUND MANAGEMENT LLC 0.31% of their portfolio NEW YORK, NY 200,000200.0k $23.0m $23.0m 0.31% New
40 GABELLI FUNDS LLC 0.15% of their portfolio Rye, NY 195,900195.9k $22.5m $22.5m 0.15% New
41 UBS Group AG 0.00% of their portfolio ZURICH, V8 194,709194.7k $22.4m $22.4m 0.00% Reduced -121.9k -121,903
42 Verition Fund Management LLC 0.21% of their portfolio GREENWICH, CT 187,354187.4k $21.5m $21.5m 0.21% New
43 WATER ISLAND CAPITAL LLC 2.81% of their portfolio NEW YORK, NY 183,409183.4k $21.1m $21.1m 2.81% New
44 Man Group plc 0.04% of their portfolio LONDON, X0 180,000180.0k $20.7m $20.7m 0.04% Added +176.7k +176,678
45 Rock Springs Capital Management LP 1.15% of their portfolio Baltimore, MD 169,859169.9k $19.5m $19.5m 1.15% Unchanged
46 GABELLI & Co INVESTMENT ADVISERS, INC. 2.60% of their portfolio Rye, NY 152,400152.4k $17.5m $17.5m 2.60% New
47 BNP PARIBAS FINANCIAL MARKETS 0.01% of their portfolio PARIS, I0 151,558151.6k $17.4m $17.4m 0.01% Added +148.0k +147,953
48 Groupe la Francaise 0.24% of their portfolio PARIS, I0 151,046151.0k $17.3m $17.3m 0.24% New
49 Bank of New York Mellon Corp 0.00% of their portfolio NEW YORK, NY 143,099143.1k $16.4m $16.4m 0.00% Added +19.9k +19,928
50 CREDIT INDUSTRIEL ET COMMERCIAL 2.46% of their portfolio PARIS FRANCE, I0 134,648134.6k $15.5m $15.5m 2.46% New
51 Woodline Partners LP 0.05% of their portfolio San Francisco, CA 123,750123.8k $14.2m $14.2m 0.05% Reduced -614.1k -614,074
52 GARDNER LEWIS ASSET MANAGEMENT L P 3.06% of their portfolio CHADDS FORD, PA 123,197123.2k $14.1m $14.1m 3.06% New
53 Hudson Bay Capital Management LP 0.08% of their portfolio STAMFORD, CT 122,900122.9k $14.1m $14.1m 0.08% Reduced -278.0k -278,042
54 PICTON MAHONEY ASSET MANAGEMENT 0.14% of their portfolio Toronto, A6 120,000120.0k $13.8m $13.8m 0.14% New
55 FMR LLC 0.00% of their portfolio BOSTON, MA 119,378119.4k $13.7m $13.7m 0.00% Reduced -3.4m -3,444,350
56 Slotnik Capital, LLC 4.03% of their portfolio DALLAS, TX 118,000118.0k $13.5m $13.5m 4.03% New
57 ODDO BHF ASSET MANAGEMENT SAS 0.52% of their portfolio PARIS, I0 115,000115.0k $13.2m $13.2m 0.52% Not comparable
58 PRELUDE CAPITAL MANAGEMENT, LLC 0.87% of their portfolio NEW YORK, NY 98,84998.8k $11.3m $11.3m 0.87% New
59 RENAISSANCE TECHNOLOGIES LLC 0.02% of their portfolio NEW YORK, NY 96,40096.4k $11.1m $11.1m 0.02% New
60 Chicago Capital Management, LLC 6.66% of their portfolio CHICAGO, IL 92,95193.0k $8.0m $8.0m 6.66% New
61 JANUS HENDERSON GROUP PLC 0.00% of their portfolio LONDON, X0 90,28090.3k $10.4m $10.4m 0.00% Reduced -829.3k -829,298
62 CIBRA Capital Ltd 4.91% of their portfolio LONDON, X0 88,62388.6k $10.2m $10.2m 4.91% New
63 Nuveen, LLC 0.00% of their portfolio CHARLOTTE, NC 85,29485.3k $9.8m $9.8m 0.00% Added +3.4k +3,350
64 DEUTSCHE BANK AG\ 0.00% of their portfolio FRANKFURT AM MAIN, 2M 80,66480.7k $9.3m $9.3m 0.00% Reduced -152.9k -152,928
65 Cinctive Capital Management LP 0.60% of their portfolio New York, NY 80,00080.0k $9.2m $9.2m 0.60% New
66 Sagefield Capital LP 0.54% of their portfolio DALLAS, TX 65,09765.1k $7.5m $7.5m 0.54% New
67 Athos Capital Ltd 2.30% of their portfolio HONG KONG, K3 64,90064.9k $7.5m $7.5m 2.30% New
68 Russell Investments Group, Ltd. 0.01% of their portfolio Seattle, WA 61,90561.9k $7.1m $7.1m 0.01% Reduced -68.6k -68,615
69 SAMSARA BIOCAPITAL, LLC 0.68% of their portfolio PALO ALTO, CA 60,87360.9k $7.0m $7.0m 0.68% Unchanged
70 UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC 0.00% of their portfolio NEW YORK, NY 57,28957.3k $6.6m $6.6m 0.00% Reduced -103.7k -103,746
71 Voleon Capital Management LP 0.14% of their portfolio BERKELEY, CA 56,72056.7k $6.5m $6.5m 0.14% New
72 PSquared Asset Management AG 2.21% of their portfolio ZURICH, V8 55,25155.3k $6.3m $6.3m 2.21% New
73 Swiss National Bank 0.00% of their portfolio ZURICH, V8 54,70054.7k $6.3m $6.3m 0.00% Unchanged
74 Twin Securities, Inc. 3.06% of their portfolio New York, NY 53,98254.0k $6.2m $6.2m 3.06% New
75 Susquehanna Portfolio Strategies, LLC 0.09% of their portfolio Bala Cynwyd, PA 50,93850.9k $5.8m $5.8m 0.09% Unchanged
76 HARVEST MANAGEMENT LLC 3.05% of their portfolio New York, NY 50,00050.0k $5.7m $5.7m 3.05% New
77 CONGRESS ASSET MANAGEMENT CO 0.04% of their portfolio BOSTON, MA 47,55147.6k $5.5m $5.5m 0.04% Added +21.6k +21,552
78 Invesco Ltd. 0.00% of their portfolio ATLANTA, GA 47,28047.3k $5.4m $5.4m 0.00% Added +6.9k +6,908
79 PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio BALTIMORE, MD 45,95446.0k $5.3m $5.3m 0.00% Reduced -1.6m -1,564,847
80 RHUMBLINE ADVISERS 0.00% of their portfolio BOSTON, MA 45,21145.2k $5.2m $5.2m 0.00% Added +859 +859
81 Maven Securities LTD 0.44% of their portfolio ST HELIER, Y9 42,50042.5k $4.9m $4.9m 0.44% New
82 Rafferty Asset Management, LLC 0.02% of their portfolio New York, NY 39,44139.4k $4.5m $4.5m 0.02% Reduced -30.1k -30,074
83 CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM 0.00% of their portfolio WEST SACRAMENTO, CA 34,88634.9k $4.0m $4.0m 0.00% Added +7.8k +7,771
84 EQUITEC PROPRIETARY MARKETS, LLC 8.91% of their portfolio CHICAGO, IL 33,57433.6k $3.9m $3.9m 8.91% New
85 ADAR1 Capital Management, LLC 0.22% of their portfolio AUSTIN, TX 32,08432.1k $3.7m $3.7m 0.22% Added +600 +600
86 FIFTH LANE CAPITAL, LP 4.33% of their portfolio Austin, TX 31,04431.0k $3.6m $3.6m 4.33% New
87 ABC ARBITRAGE SA 0.46% of their portfolio PARIS, I0 30,34730.3k $3.5m $3.5m 0.46% New
88 DekaBank Deutsche Girozentrale 0.01% of their portfolio FRANKFURT, 2M 30,00030.0k $3.5m $3.5m 0.01% Unchanged
89 HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND 0.01% of their portfolio TORONTO, A6 30,00030.0k $3.4m $3.4m 0.01% New
90 VANGUARD ASSET MANAGEMENT, Ltd 0.00% of their portfolio London, EC4N 8AF, X0 27,52127.5k $3.2m $3.2m 0.00% First filing
91 Squarepoint Ops LLC 0.01% of their portfolio NEW YORK, NY 27,14527.1k $3.1m $3.1m 0.01% Reduced -22.7k -22,730
92 New York Life Investment Management LLC 0.03% of their portfolio New York, NY 26,24326.2k $3.0m $3.0m 0.03% New
93 SG Americas Securities, LLC 0.00% of their portfolio NEW YORK, NY 24,71324.7k $2.8m $2.8m 0.00% Added +12.7k +12,672
94 Skandinaviska Enskilda Banken AB (publ) 0.06% of their portfolio STOCKHOLM, V7 24,00024.0k $2.8m $2.8m 0.06% New
95 Yakira Capital Management, Inc. 0.81% of their portfolio Westport, CT 24,00024.0k $2.8m $2.8m 0.81% New
96 Legal & General Group Plc 0.00% of their portfolio London, X0 21,88821.9k $2.5m $2.5m 0.00% Reduced -7.7k -7,677
97 CITADEL ADVISORS LLC 0.00% of their portfolio MIAMI, FL 21,80621.8k $2.5m $2.5m 0.00% Reduced -1.5m -1,478,417
98 Erste Asset Management GmbH 0.02% of their portfolio VIENNA, C4 21,00021.0k $2.4m $2.4m 0.02% Unchanged
99 MetLife Investment Management, LLC 0.01% of their portfolio Whippany, NJ 20,91420.9k $2.4m $2.4m 0.01% Added +1.6k +1,570
100 MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. 0.00% of their portfolio CAUSEWAY BAY, K3 20,80620.8k $2.4m $2.4m 0.00% Added +804 +804