Advanced Drainage Systems, Inc.
MX ˙ BMV ˙ US00790R1041
SecurityMX:WMS / Advanced Drainage Systems, Inc.
InstitutionBamco Inc /ny/
Latest Disclosed Ownership291,152 shares
Latest Disclosed Value $ 39,925,674
Bamco Inc /ny/ reports 1.20% decrease in ownership of WMS / Advanced Drainage Systems, Inc.

On May 15, 2026 - Bamco Inc /ny/ filed a 13F-HR form disclosing ownership of 291,152 shares of Advanced Drainage Systems, Inc. (MX:WMS) valued at $39,925,674 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 294,678 shares of Advanced Drainage Systems, Inc.. This represents a change in shares of -1.20% 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)
2026-05-15 2026-03-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 291,152 -3,526 -1.20 39,926 -6.45 0.1205
2026-02-17 2025-12-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 294,678 0 0.00 42,678 4.42 0.1156
2025-11-14 2025-09-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 294,678 75 0.03 40,872 20.78 0.1084
2025-08-14 2025-06-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 294,603 -13,252 -4.30 33,838 1.17 0.0917
2025-05-15 2025-03-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 307,855 307,855 33,448 0.0982
2020-08-14 2020-06-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 0 -500,000 -100.00 0 -100.00
2020-05-15 2020-03-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 500,000 -325,000 -39.39 14,720 -54.06 0.0721
2020-02-18 2019-12-31 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 825,000 0 0.00 32,043 20.36 0.1224
2019-11-14 2019-09-30 13F ADVANCED DRAIN SYS INC DEL COM 00790R104 825,000 825,000 26,623 0.1095
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.