Advanced Drainage Systems, Inc.
MX ˙ BMV ˙ US00790R1041
SecurityMX:WMS / Advanced Drainage Systems, Inc.
InstitutionJanus Henderson Group Plc
Latest Disclosed Ownership592,581 shares
Latest Disclosed Value $ 81,278,314
Janus Henderson Group Plc reports 1.04% decrease in ownership of WMS / Advanced Drainage Systems, Inc.

On May 18, 2026 - Janus Henderson Group Plc filed a 13F-HR/A form disclosing ownership of 592,581 shares of Advanced Drainage Systems, Inc. (MX:WMS) valued at $81,278,314 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 598,810 shares of Advanced Drainage Systems, Inc.. This represents a change in shares of -1.04% 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 ADVANCED DRAIN SYS INC DEL COM 00790R104 592,581 -6,229 -1.04 81,278 -6.28 0.0388
2026-05-15 2026-03-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 592,581 -6,229 81,278 0.0151
2026-02-17 2025-12-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 598,810 18,146 3.13 86,729 7.58 0.0388
2025-11-14 2025-09-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 580,664 -4,877 -0.83 80,616 19.89 0.0368
2025-08-14 2025-06-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 585,541 -64,644 -9.94 67,244 -4.47 0.0330
2025-05-15 2025-03-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 650,185 6,129 0.95 70,390 -5.45 0.0386
2025-02-14 2024-12-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 644,056 54,916 9.32 74,444 -19.59 0.0378
2024-11-14 2024-09-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 589,140 953 0.16 92,578 -1.79 0.0474
2024-08-14 2024-06-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 588,187 14,970 2.61 94,267 -4.63 0.0505
2024-05-15 2024-03-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 573,217 -16,886 -2.86 98,842 19.06 0.0539
2024-02-14 2023-12-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 590,103 9,036 1.56 83,023 25.46 0.0495
2023-11-14 2023-09-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 581,067 -694 -0.12 66,176 0.06 0.0433
2023-08-14 2023-06-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 581,761 27,018 4.87 66,135 41.60 0.0411
2023-05-15 2023-03-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 554,743 61,416 12.45 46,707 15.53 0.0308
2023-02-14 2022-12-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 493,327 102,683 26.29 40,429 -16.81 0.0289
2023-01-13 2022-09-30 13F/A-1 ADVANCED DRAIN SYS INC DEL COM 00790R104 390,644 -7,850 -1.97 48,598 35.35 0.0364
2022-11-14 2022-09-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 390,644 -7,850 48,598 0.0123
2022-08-15 2022-06-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 398,494 14,328 3.73 35,905 -21.34 0.0248
2022-05-16 2022-03-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 384,166 -45,230 -10.53 45,644 -21.92 0.0220
2022-02-14 2021-12-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 429,396 404,126 1,599.23 58,456 2,038.89 0.0244
2021-11-16 2021-09-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 25,270 25,270 2,733 0.0012
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.