Vault-13

MASIMO CORP MASI

COM · Common Stock · CUSIP 574795100 · ISIN US5747951003

451 institutional holders +59 vs Q4 2025
54,512,57554.5m shares reported held*
$9.7bnreported value*
119 new 140 added 107 reduced 71 sold out net sold ≈ $587.5m (-3.2m 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 ($18.7m this quarter). Holder counts are more reliable. Implied quarter-end price ≈ $177.40. Options: 17 managers hold calls ($275.7m notional), 8 hold puts ($25.3m).

Trends to Q1 2026

Institutional holders

Managers reporting a position, each quarter

0200400600Q3 22: 420Q4 22: 405Q1 23: 429Q2 23: 417Q3 23: 358Q4 23: 343Q1 24: 341Q2 24: 353Q3 24: 363Q4 24: 367Q1 25: 394Q2 25: 380Q3 25: 358Q4 25: 392Q1 26: 451451Q3 22Q3 23Q3 24Q3 25Q1 26
Numbers
QuarterHolders
Q3 2022420
Q4 2022405
Q1 2023429
Q2 2023417
Q3 2023358
Q4 2023343
Q1 2024341
Q2 2024353
Q3 2024363
Q4 2024367
Q1 2025394
Q2 2025380
Q3 2025358
Q4 2025392
Q1 2026451

Buyers vs sellers

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

Bought or addedCut or sold out
4000400Q2 24: 170 bought or addedQ2 24: 151 cut or sold outQ3 24: 169 bought or addedQ3 24: 170 cut or sold outQ3 24Q4 24: 162 bought or addedQ4 24: 169 cut or sold outQ1 25: 206 bought or addedQ1 25: 161 cut or sold outQ1 25Q2 25: 166 bought or addedQ2 25: 195 cut or sold outQ3 25: 164 bought or addedQ3 25: 184 cut or sold outQ3 25Q4 25: 174 bought or addedQ4 25: 182 cut or sold outQ1 26: 259 bought or addedQ1 26: 178 cut or sold outQ1 26
Numbers
QuarterBought or addedCut or sold out
Q2 2024170151
Q3 2024169170
Q4 2024162169
Q1 2025206161
Q2 2025166195
Q3 2025164184
Q4 2025174182
Q1 2026259178

Calls vs puts

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

CallsPuts
$0$100m$200m$300mQ2 25 calls: $10.1mQ2 25 puts: $3.9mQ2 25P/C 0.38Q3 25 calls: $5.5mQ3 25 puts: $5.5mQ3 25P/C 1.00Q4 25 calls: $3.6mQ4 25 puts: $8.4mQ4 25P/C 2.37Q1 26 calls: $275.7mQ1 26 puts: $25.3mQ1 26P/C 0.09
Numbers
QuarterCallsPutsP/C
Q2 2025$10.1m$3.9m0.38
Q3 2025$5.5m$5.5m1.00
Q4 2025$3.6m$8.4m2.37
Q1 2026$275.7m$25.3m0.09

Biggest buyers

Pentwater Capital Management LP New +3,176,000+3.2m
BARCLAYS PLC Added +2,685,627+2.7m
HBK INVESTMENTS L P New +2,576,109+2.6m
MILLENNIUM MANAGEMENT LLC Added +800,888+800.9k
Balyasny Asset Management L.P. New +770,986+771.0k
SG Americas Securities, LLC Added +506,395+506.4k
FIL Ltd New +482,000+482.0k
First Trust Capital Management L.P. New +479,403+479.4k
HSBC HOLDINGS PLC New +473,434+473.4k
JPMORGAN CHASE & CO Added +454,847+454.8k

Biggest sellers

FMR LLC Reduced -6,413,341-6.4m
BlackRock, Inc. Reduced -4,211,041-4.2m
T. Rowe Price Investment Management, Inc. Sold out -2,930,451-2.9m
NAYA CAPITAL MANAGEMENT UK LTD Sold out -1,560,697-1.6m
Alyeska Investment Group, L.P. Sold out -1,259,307-1.3m
WESTFIELD CAPITAL MANAGEMENT CO LP Reduced -1,180,820-1.2m
RTW INVESTMENTS, LP Sold out -683,294-683.3k
Liontrust Investment Partners LLP Reduced -607,658-607.7k
VIKING GLOBAL INVESTORS LP Sold out -514,340-514.3k
AMERIPRISE FINANCIAL INC Reduced -403,204-403.2k

Biggest calls

Walleye Trading LLC New $64.5m362.6k shares
MILLENNIUM MANAGEMENT LLC New $51.3m288.6k shares
Caption Management, LLC New $41.4m232.9k shares
SUSQUEHANNA INTERNATIONAL GROUP, LLP Added $36.9m207.6k shares
TUDOR INVESTMENT CORP ET AL New $36.2m203.5k shares
Balyasny Asset Management L.P. New $15.1m85.1k shares
CSS LLC/IL New $9.6m53.9k shares
SIMPLEX TRADING, LLC New $8.3m46.4k shares
CITADEL ADVISORS LLC Added $4.9m27.6k shares
Polar Asset Management Partners Inc. New $4.4m25.0k shares

Biggest puts

SUSQUEHANNA INTERNATIONAL GROUP, LLP Added $11.8m66.2k shares
Walleye Trading LLC New $4.9m27.8k shares
CITADEL ADVISORS LLC Added $4.2m23.8k shares
LOGAN CAPITAL MANAGEMENT INC New $3.6m20.5k shares
IMC-Chicago, LLC New $515.8k2.9k shares
SIMPLEX TRADING, LLC New $195.7k1.1k shares
CSS LLC/IL New $17.8k100 shares
FNY Investment Advisers, LLC New $01 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
BlackRock, Inc. 13G · institution filed 2025-02-07 7.9% 4.2m 2025-02-07
KIANI JOE E 13G · exempt (held before listing) -3.8 pts · filed 2026-05-14 6.5% -3.8 pts 3.7m 2026-05-14
BARCLAYS PLC 13G · institution new · filed 2026-05-14 5.5% new 2.9m 2026-05-14

Fell to 5% or below in the last year: Pentwater Capital Management LP (0.0%, 2026-08-14), Politan Capital Management LP (0.0%, 2026-06-11), BlackRock Portfolio Management LLC (0.2%, 2026-04-30; now reported by BlackRock, Inc.), VANGUARD GROUP INC (0.0%, 2026-03-27), FMR LLC (4.5%, 2026-03-06)

Holders, Q1 2026

#ManagerLocationShares Value% of their portfolioChangeShares change
1 BlackRock, Inc. 0.01% of their portfolio New York, NY 4,644,5784.6m $826.1m $826.1m 0.01% Reduced -4.2m -4,211,041
2 Politan Capital Management LP 82.89% of their portfolio NEW YORK, NY 4,589,6484.6m $816.4m $816.4m 82.89% Unchanged
3 Pentwater Capital Management LP 4.01% of their portfolio Naples, FL 3,176,0003.2m $564.9m $564.9m 4.01% New
4 BARCLAYS PLC 0.17% of their portfolio LONDON, X0 2,743,9852.7m $488.1m $488.1m 0.17% Added +2.7m +2,685,627
5 HBK INVESTMENTS L P 5.77% of their portfolio DALLAS, TX 2,576,1092.6m $458.2m $458.2m 5.77% New
6 MASSACHUSETTS FINANCIAL SERVICES CO /MA/ 0.14% of their portfolio Boston, MA 2,342,7902.3m $416.7m $416.7m 0.14% Reduced -321.1k -321,085
7 VANGUARD CAPITAL MANAGEMENT LLC 0.01% of their portfolio MALVERN, PA 2,050,0452.1m $364.6m $364.6m 0.01% First filing
8 VANGUARD PORTFOLIO MANAGEMENT LLC 0.02% of their portfolio MALVERN, PA 2,006,8612.0m $357.0m $357.0m 0.02% First filing
9 FMR LLC 0.01% of their portfolio BOSTON, MA 1,450,8231.5m $258.1m $258.1m 0.01% Reduced -6.4m -6,413,341
10 STATE STREET CORP 0.01% of their portfolio BOSTON, MA 1,437,7241.4m $255.7m $255.7m 0.01% Added +22.5k +22,528
11 MILLENNIUM MANAGEMENT LLC 0.13% of their portfolio NEW YORK, NY 988,853988.9k $175.9m $175.9m 0.13% Added +800.9k +800,888
12 GOLDMAN SACHS GROUP INC 0.02% of their portfolio NEW YORK, NY 984,192984.2k $175.1m $175.1m 0.02% Added +347.5k +347,494
13 GEODE CAPITAL MANAGEMENT, LLC 0.01% of their portfolio BOSTON, MA 956,736956.7k $170.2m $170.2m 0.01% Added +2.8k +2,760
14 AQR CAPITAL MANAGEMENT LLC 0.07% of their portfolio Greenwich, CT 831,966832.0k $147.4m $147.4m 0.07% Reduced -259.4k -259,360
15 Balyasny Asset Management L.P. 0.27% of their portfolio Chicago, IL 770,986771.0k $137.1m $137.1m 0.27% New
16 MORGAN STANLEY 0.01% of their portfolio NEW YORK, NY 752,417752.4k $133.8m $133.8m 0.01% Reduced -168.3k -168,318
17 Davidson Kempner Capital Management LP 1.85% of their portfolio New York, NY 585,988586.0k $104.2m $104.2m 1.85% Not comparable
18 JPMORGAN CHASE & CO 0.01% of their portfolio NEW YORK, NY 572,645572.6k $101.5m $101.5m 0.01% Added +454.8k +454,847
19 CITIGROUP INC 0.06% of their portfolio NEW YORK, NY 533,388533.4k $94.9m $94.9m 0.06% Added +412.2k +412,157
20 SG Americas Securities, LLC 0.10% of their portfolio NEW YORK, NY 522,824522.8k $93.0m $93.0m 0.10% Added +506.4k +506,395
21 FIL Ltd 0.07% of their portfolio HAMILTON, D0 482,000482.0k $85.7m $85.7m 0.07% New
22 First Trust Capital Management L.P. 4.48% of their portfolio CHICAGO, IL 479,403479.4k $85.3m $85.3m 4.48% New
23 HSBC HOLDINGS PLC 0.05% of their portfolio LONDON, X0 473,434473.4k $84.3m $84.3m 0.05% New
24 UBS Group AG 0.01% of their portfolio ZURICH, V8 468,257468.3k $83.3m $83.3m 0.01% Reduced -131.0k -131,017
25 ALLIANCEBERNSTEIN L.P. 0.02% of their portfolio NASHVILLE, TN 455,354455.4k $59.2m $59.2m 0.02% Added +401.1k +401,131
26 Magnetar Financial LLC 0.77% of their portfolio EVANSTON, IL 427,081427.1k $76.0m $76.0m 0.77% Added +421.6k +421,626
27 AQR Arbitrage LLC 1.21% of their portfolio Greenwich, CT 416,956417.0k $73.9m $73.9m 1.21% New
28 O'Connor Alternative Investments LLC 3.85% of their portfolio NEW YORK, NY 412,903412.9k $73.4m $73.4m 3.85% First filing
29 NEUBERGER BERMAN GROUP LLC 0.05% of their portfolio NEW YORK, NY 403,309403.3k $71.7m $71.7m 0.05% Added +398.3k +398,303
30 NORTHERN TRUST CORP 0.01% of their portfolio CHICAGO, IL 390,437390.4k $69.4m $69.4m 0.01% Added +10.0k +9,973
31 Squarepoint Ops LLC 0.15% of their portfolio NEW YORK, NY 389,359389.4k $69.3m $69.3m 0.15% Reduced -194.4k -194,388
32 CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.01% of their portfolio SAN FRANCISCO, CA 386,898386.9k $68.8m $68.8m 0.01% Added +25.0k +25,002
33 Capital Research Global Investors 0.01% of their portfolio Los Angeles, CA 359,058359.1k $63.9m $63.9m 0.01% Reduced -278.8k -278,836
34 Gotham Asset Management, LLC 0.19% of their portfolio NEW YORK, NY 341,468341.5k $60.7m $60.7m 0.19% Reduced -726 -726
35 WESTFIELD CAPITAL MANAGEMENT CO LP 0.25% of their portfolio BOSTON, MA 341,229341.2k $60.7m $60.7m 0.25% Reduced -1.2m -1,180,820
36 Hudson Bay Capital Management LP 0.35% of their portfolio STAMFORD, CT 330,679330.7k $58.8m $58.8m 0.35% New
37 Corient Private Wealth LP 0.08% of their portfolio MIAMI, FL 321,600321.6k $57.2m $57.2m 0.08% Reduced -360.4k -360,360
38 Fort Baker Capital Management LP 4.93% of their portfolio Larkspur, CA 312,720312.7k $55.6m $55.6m 4.93% New
39 NEXPOINT ASSET MANAGEMENT, L.P. 3.85% of their portfolio Dallas, TX 310,130310.1k $55.2m $55.2m 3.85% New
40 CAPITOLIS LIQUID GLOBAL MARKETS LLC 0.35% of their portfolio NEW YORK, NY 309,102309.1k $55.0m $55.0m 0.35% First filing
41 Bank of New York Mellon Corp 0.01% of their portfolio NEW YORK, NY 306,400306.4k $54.5m $54.5m 0.01% Reduced -2.1k -2,085
42 Qube Research & Technologies Ltd 0.07% of their portfolio LONDON, X0 291,481291.5k $51.8m $51.8m 0.07% Reduced -2.1k -2,055
43 VANGUARD FIDUCIARY TRUST CO 0.01% of their portfolio MALVERN, PA 289,867289.9k $51.6m $51.6m 0.01% First filing
44 CITADEL ADVISORS LLC 0.04% of their portfolio MIAMI, FL 281,366281.4k $50.0m $50.0m 0.04% Added +238.3k +238,314
45 WHITEBOX ADVISORS LLC 0.68% of their portfolio MINNEAPOLIS, MN 270,001270.0k $48.0m $48.0m 0.68% New
46 HRT FINANCIAL LP 0.17% of their portfolio NEW YORK, NY 264,837264.8k $47.1m $47.1m 0.17% Added +172.1k +172,061
47 NUANCE INVESTMENTS, LLC 6.07% of their portfolio Kansas City, MO 244,704244.7k $43.5m $43.5m 6.07% New
48 Amundi 0.01% of their portfolio Paris, I0 243,143243.1k $43.2m $43.2m 0.01% Added +199.3k +199,283
49 Slotnik Capital, LLC 12.70% of their portfolio DALLAS, TX 240,300240.3k $42.7m $42.7m 12.70% New
50 RENAISSANCE TECHNOLOGIES LLC 0.07% of their portfolio NEW YORK, NY 239,500239.5k $42.6m $42.6m 0.07% Added +179.6k +179,600
51 Polar Asset Management Partners Inc. 0.98% of their portfolio TORONTO, A6 232,026232.0k $41.3m $41.3m 0.98% New
52 BANK OF AMERICA CORP /DE/ 0.00% of their portfolio CHARLOTTE, NC 232,003232.0k $41.3m $41.3m 0.00% Reduced -52.7k -52,699
53 MUFG Securities EMEA plc 0.60% of their portfolio LONDON, X0 225,400225.4k $40.1m $40.1m 0.60% New
54 Beryl Capital Management LLC 35.54% of their portfolio REDONDO BEACH, CA 217,103217.1k $38.6m $38.6m 35.54% New
55 CANADA PENSION PLAN INVESTMENT BOARD 0.02% of their portfolio TORONTO ONTARIO, A6 209,500209.5k $37.3m $37.3m 0.02% Added +171.0k +171,000
56 Erste Asset Management GmbH 0.33% of their portfolio VIENNA, C4 200,000200.0k $35.5m $35.5m 0.33% Unchanged
57 WATER ISLAND CAPITAL LLC 4.60% of their portfolio NEW YORK, NY 194,197194.2k $34.5m $34.5m 4.60% New
58 ALPINE ASSOCIATES MANAGEMENT INC. 1.98% of their portfolio PALM BEACH, FL 189,000189.0k $33.6m $33.6m 1.98% New
59 AMERICAN CENTURY COMPANIES INC 0.02% of their portfolio KANSAS CITY, MO 188,073188.1k $33.5m $33.5m 0.02% Added +9.3k +9,315
60 ARROWSTREET CAPITAL, LIMITED PARTNERSHIP 0.02% of their portfolio BOSTON, MA 172,588172.6k $30.7m $30.7m 0.02% New
61 READYSTATE ASSET MANAGEMENT LP 1.78% of their portfolio CHICAGO, IL 171,115171.1k $30.4m $30.4m 1.78% New
62 RAYMOND JAMES FINANCIAL INC 0.01% of their portfolio ST. PETERSBURG, FL 170,527170.5k $30.3m $30.3m 0.01% Reduced -16.0k -15,983
63 Man Group plc 0.06% of their portfolio LONDON, X0 166,235166.2k $29.6m $29.6m 0.06% Added +18.8k +18,819
64 DIMENSIONAL FUND ADVISORS LP 0.01% of their portfolio AUSTIN, TX 164,402164.4k $29.2m $29.2m 0.01% Reduced -9.5k -9,548
65 GLAZER CAPITAL, LLC 0.60% of their portfolio New York, NY 157,858157.9k $28.1m $28.1m 0.60% New
66 Woodline Partners LP 0.10% of their portfolio San Francisco, CA 153,234153.2k $27.3m $27.3m 0.10% New
67 BANK OF NOVA SCOTIA 0.05% of their portfolio TORONTO, A6 152,584152.6k $27.1m $27.1m 0.05% Added +147.3k +147,337
68 TUDOR INVESTMENT CORP ET AL 0.14% of their portfolio STAMFORD, CT 143,884143.9k $25.6m $25.6m 0.14% Added +127.6k +127,642
69 Capula Management Ltd 0.22% of their portfolio Grand Cayman, E9 142,800142.8k $25.4m $25.4m 0.22% Not comparable
70 Champlain Investment Partners, LLC 0.32% of their portfolio BURLINGTON, VT 141,284141.3k $25.1m $25.1m 0.32% New
71 Westchester Capital Management, LLC 1.19% of their portfolio VALHALLA, NY 138,428138.4k $24.6m $24.6m 1.19% New
72 Grantham, Mayo, Van Otterloo & Co. LLC 0.06% of their portfolio Boston, MA 137,617137.6k $24.5m $24.5m 0.06% Reduced -6.2k -6,208
73 TIG Advisors, LLC 1.15% of their portfolio New York, NY 135,197135.2k $24.0m $24.0m 1.15% New
74 UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC 0.00% of their portfolio NEW YORK, NY 133,689133.7k $23.8m $23.8m 0.00% Added +14.7k +14,725
75 RHUMBLINE ADVISERS 0.02% of their portfolio BOSTON, MA 129,619129.6k $23.1m $23.1m 0.02% Added +5.1k +5,063
76 GABELLI FUNDS LLC 0.15% of their portfolio Rye, NY 126,082126.1k $22.4m $22.4m 0.15% Added +93.4k +93,382
77 GW&K Investment Management, LLC 0.19% of their portfolio BOSTON, MA 122,781122.8k $21.8m $21.8m 0.19% Added +3.4k +3,419
78 Sagefield Capital LP 1.56% of their portfolio DALLAS, TX 122,240122.2k $21.7m $21.7m 1.56% New
79 Schonfeld Strategic Advisors LLC 0.17% of their portfolio NEW YORK, NY 117,297117.3k $20.9m $20.9m 0.17% Reduced -147.7k -147,739
80 WINTON GROUP Ltd 0.70% of their portfolio LONDON, X0 112,783112.8k $20.1m $20.1m 0.70% New
81 Weiss Asset Management LP 0.37% of their portfolio BOSTON, MA 112,600112.6k $20.0m $20.0m 0.37% Not comparable
82 Nuveen, LLC 0.01% of their portfolio CHARLOTTE, NC 111,542111.5k $19.8m $19.8m 0.01% Reduced -112.5k -112,526
83 NOMURA HOLDINGS INC 0.16% of their portfolio TOKYO, M0 109,390109.4k $19.5m $19.5m 0.16% New
84 Blackstone Inc. 0.08% of their portfolio NEW YORK, NY 109,383109.4k $19.5m $19.5m 0.08% Not comparable
85 PRINCIPAL FINANCIAL GROUP INC 0.01% of their portfolio DES MOINES, IA 102,718102.7k $18.3m $18.3m 0.01% Added +4.9k +4,860
86 SOROS FUND MANAGEMENT LLC 0.25% of their portfolio NEW YORK, NY 100,838100.8k $17.9m $17.9m 0.25% New
87 Kryger Capital LLC 1.27% of their portfolio HAMILTON, D0 100,589100.6k $17.9m $17.9m 1.27% First filing
88 SCHRODER INVESTMENT MANAGEMENT GROUP 0.01% of their portfolio London, X0 96,17996.2k $17.1m $17.1m 0.01% Reduced -379.3k -379,325
89 GAMCO INVESTORS, INC. ET AL 0.16% of their portfolio GREENWICH, CT 92,00092.0k $16.4m $16.4m 0.16% Added +9.0k +9,000
90 MARSHALL WACE, LLP 0.02% of their portfolio LONDON, X0 90,65790.7k $16.1m $16.1m 0.02% Reduced -128.7k -128,655
91 CIBRA Capital Ltd 7.76% of their portfolio LONDON, X0 90,37690.4k $16.1m $16.1m 7.76% New
92 Swiss National Bank 0.01% of their portfolio ZURICH, V8 90,30090.3k $16.1m $16.1m 0.01% Reduced -800 -800
93 DEUTSCHE BANK AG\ 0.01% of their portfolio FRANKFURT AM MAIN, 2M 89,38789.4k $15.9m $15.9m 0.01% Added +82.7k +82,651
94 GABELLI & Co INVESTMENT ADVISERS, INC. 2.34% of their portfolio Rye, NY 88,65088.7k $15.8m $15.8m 2.34% New
95 California Public Employees Retirement System 0.01% of their portfolio Sacramento, CA 77,39777.4k $13.8m $13.8m 0.01% Added +14.0k +14,038
96 VOLORIDGE INVESTMENT MANAGEMENT, LLC 0.05% of their portfolio JUPITER, FL 70,00070.0k $12.5m $12.5m 0.05% Added +30.4k +30,443
97 Invesco Ltd. 0.00% of their portfolio ATLANTA, GA 69,14469.1k $12.3m $12.3m 0.00% Reduced -250.2k -250,164
98 HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND 0.02% of their portfolio TORONTO, A6 67,60067.6k $12.0m $12.0m 0.02% New
99 Verition Fund Management LLC 0.12% of their portfolio GREENWICH, CT 66,85366.9k $11.9m $11.9m 0.12% Added +13.8k +13,833
100 AMERIPRISE FINANCIAL INC 0.00% of their portfolio MINNEAPOLIS, MN 65,20365.2k $11.6m $11.6m 0.00% Reduced -403.2k -403,204