Arista Networks, Inc.
MX ˙ BMV ˙ US0404132054
SecurityMX:ANET / Arista Networks, Inc.
InstitutionJanus Henderson Group Plc
Latest Disclosed Ownership4,880,273 shares
Latest Disclosed Value $ 599,195,458
Janus Henderson Group Plc reports 44.49% increase in ownership of ANET / Arista Networks, Inc.

On May 18, 2026 - Janus Henderson Group Plc filed a 13F-HR/A form disclosing ownership of 4,880,273 shares of Arista Networks, Inc. (MX:ANET) valued at $599,195,458 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 3,377,685 shares of Arista Networks, Inc.. This represents a change in shares of 44.49% during the quarter.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-18 2026-03-31 13F/A-1 ARISTA NETWORKS COM SHS 040413205 4,880,273 1,502,588 44.49 599,195 35.40 0.2861
2026-05-15 2026-03-31 13F ARISTA NETWORKS COM SHS 040413205 4,880,273 1,502,588 599,195 0.1112
2026-02-17 2025-12-31 13F ARISTA NETWORKS COM SHS 040413205 3,377,685 1,387,902 69.75 442,542 52.63 0.1982
2025-11-14 2025-09-30 13F ARISTA NETWORKS COM SHS 040413205 1,989,783 971,662 95.44 289,935 178.26 0.1324
2025-08-14 2025-06-30 13F ARISTA NETWORKS COM SHS 040413205 1,018,121 43,688 4.48 104,194 37.24 0.0511
2025-05-15 2025-03-31 13F ARISTA NETWORKS COM SHS 040413205 974,433 2,886 0.30 75,923 -29.33 0.0416
2025-02-14 2024-12-31 13F ARISTA NETWORKS COM SHS 040413205 971,547 614,483 172.09 107,439 -21.58 0.0546
2024-11-14 2024-09-30 13F ARISTA NETWORKS COM 040413106 357,064 2,851 0.80 137,004 10.38 0.0701
2024-08-14 2024-06-30 13F ARISTA NETWORKS COM 040413106 354,213 -952 -0.27 124,125 20.59 0.0665
2024-05-15 2024-03-31 13F ARISTA NETWORKS COM 040413106 355,165 -29,232 -7.60 102,929 13.73 0.0561
2024-02-14 2023-12-31 13F ARISTA NETWORKS COM 040413106 384,397 -2,789 -0.72 90,504 27.05 0.0540
2023-11-14 2023-09-30 13F ARISTA NETWORKS COM 040413106 387,186 78,849 25.57 71,234 42.61 0.0466
2023-08-14 2023-06-30 13F ARISTA NETWORKS COM 040413106 308,337 -27,887 -8.29 49,949 -11.47 0.0311
2023-05-15 2023-03-31 13F ARISTA NETWORKS COM 040413106 336,224 -20,068 -5.63 56,420 30.48 0.0372
2023-02-14 2022-12-31 13F ARISTA NETWORKS COM 040413106 356,292 322,838 965.02 43,241 1,044.85 0.0309
2023-01-13 2022-09-30 13F/A-1 ARISTA NETWORKS COM 040413106 33,454 -2,207 -6.19 3,777 12.91 0.0028
2022-11-14 2022-09-30 13F ARISTA NETWORKS COM 040413106 33,454 -2,207 3,777 0.0028
2022-08-15 2022-06-30 13F ARISTA NETWORKS COM 040413106 35,661 -516,450 -93.54 3,345 -95.64 0.0023
2022-05-16 2022-03-31 13F ARISTA NETWORKS COM 040413106 552,111 394,891 251.17 76,731 239.52 0.0370
2022-02-14 2021-12-31 13F ARISTA NETWORKS COM 040413106 157,220 119,146 312.93 22,600 72.72 0.0094
2021-11-16 2021-09-30 13F ARISTA NETWORKS COM 040413106 38,074 -1,984 -4.95 13,085 -9.84 0.0057
2021-08-16 2021-06-30 13F ARISTA NETWORKS COM 040413106 40,058 -42,864 -51.69 14,513 -42.02 0.0062
2021-05-17 2021-03-31 13F ARISTA NETWORKS COM 040413106 82,922 4,042 5.12 25,033 9.22 0.0114
2021-02-16 2020-12-31 13F ARISTA NETWORKS COM 040413106 78,880 -15,607 -16.52 22,920 17.23 0.0106
2020-11-16 2020-09-30 13F ARISTA NETWORKS COM 040413106 94,487 29,797 46.06 19,552 43.91 0.0102
2020-08-14 2020-06-30 13F ARISTA NETWORKS COM 040413106 64,690 52,086 413.25 13,586 431.53 0.0076
2020-05-14 2020-03-31 13F ARISTA NETWORKS COM 040413106 12,604 -13,804 -52.27 2,556 -52.41 0.0018
2020-02-18 2019-12-31 13F ARISTA NETWORKS COM 040413106 26,408 -16,656 -38.68 5,371 -47.80 0.0027
2019-11-14 2019-09-30 13F ARISTA NETWORKS COM 040413106 43,064 -4,035 -8.57 10,289 -15.86 0.0056
2019-07-31 2019-06-30 13F ARISTA NETWORKS COM 040413106 47,099 7,836 19.96 12,228 -0.96 0.0067
2019-04-30 2019-03-31 13F ARISTA NETWORKS COM 040413106 39,263 -252,355 -86.54 12,346 -79.91 0.0068
2019-02-06 2018-12-31 13F ARISTA NETWORKS COM 040413106 291,618 -154,402 -34.62 61,444 -48.18 0.0392
2018-11-09 2018-09-30 13F ARISTA NETWORKS COM 040413106 446,020 21,681 5.11 118,579 8.53 0.0634
2018-08-10 2018-06-30 13F ARISTA NETWORKS COM 040413106 424,339 144,273 51.51 109,264 52.81 0.0623
2018-05-14 2018-03-31 13F ARISTA NETWORKS COM 040413106 280,066 -11,764 -4.03 71,502 4.00 0.0421
2018-03-12 2017-12-31 13F/A-1 ARISTA NETWORKS COM 040413106 291,830 -80,085 -21.53 68,750 -2.51 0.0423
2018-02-09 2017-12-31 13F ARISTA NETWORKS COM 040413106 291,830 -80,085 68,750
2017-11-14 2017-09-30 13F ARISTA NETWORKS COM 040413106 371,915 233,039 167.80 70,519 239.00 0.0452
2017-08-17 2017-06-30 13F/A-1 ARISTA NETWORKS COM 040413106 138,876 138,876 20,802 0.0142
2017-08-14 2017-06-30 13F ARISTA NETWORKS COM 040413106 138,876 138,876 20,802
2017-05-03 2017-03-31 13F ARISTA NETWORKS COM 040413106 0 -201,380 -100.00 0 -100.00
2017-01-30 2016-12-31 13F ARISTA NETWORKS COM 040413106 201,380 -47,141 -18.97 19,492 -7.74 0.1438
2016-10-24 2016-09-30 13F ARISTA NETWORKS COM 040413106 248,521 -66,349 -21.07 21,128 4.21 0.1557
2016-07-29 2016-06-30 13F ARISTA NETWORKS COM 040413106 314,870 314,870 0.00 20,274 0.1686
2016-05-12 2016-03-31 13F ARISTA NETWORKS COM 040413106 0 0 0 0.0000
2015-08-17 2015-06-30 13F ARISTA NETWORKS COM 040413106 0 -38,927 -100.00 0 -100.00
2015-06-02 2015-03-31 13F/A-1 ARISTA NETWORKS COM 040413106 38,927 0 0.00 2,745 15.92 0.0212
2015-05-15 2015-03-31 13F ARISTA NETWORKS COM 040413106 38,927 2,745
2015-02-12 2014-12-31 13F ARISTA NETWORKS COM 040413106 38,927 26,327 208.94 2,368 113.33 0.0171
2014-11-12 2014-09-30 13F ARISTA NETWORKS COM 040413106 12,600 0 0.00 1,110 41.40 0.0104
2014-08-13 2014-06-30 13F ARISTA NETWORKS COM 040413106 12,600 12,600 785 0.0073
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.