New Positions
2 managers initiated
Top five by reported value
- ISTHMUS PARTNERS, LLC$410.2K
- Ancora Advisors, LLC$35.8K
Advanced Drainage Systems Inc NEW YORK STOCK EXCHANGE, INC.:WMS
Institutional holders, quarter-over-quarter share deltas, and new and closed positions disclosed in Form 13F. Period 2025-12-31 · prior 2025-09-30.
2 new0 added3 reduced0 exited
Total Institutional Holders
5
as of 2025-12-31
Top Holder
CORBYN INVESTMENT MANAGEMENT INC/MD
$2.2M
Largest QoQ Increase
ISTHMUS PARTNERS, LLC
+2,832 sh
Largest QoQ Decrease
ELCO Management Co., LLC
-365 sh
New Positions(2)
| Manager | Shares | Δ Shares | Value | Δ Value | % Δ |
|---|---|---|---|---|---|
| ISTHMUS PARTNERS, LLC | 2,832 | +2,832 | $410.2K | +$410.2K | — |
| Ancora Advisors, LLC | 247 | +247 | $35.8K | +$35.8K | — |
Reduced(3)
| Manager | Shares | Δ Shares | Value | Δ Value | % Δ |
|---|---|---|---|---|---|
| CORBYN INVESTMENT MANAGEMENT INC/MD | 15,420 | -80 | $2.2M | +$83.4K | -0.5% |
| ELCO Management Co., LLC | 2,095 | -365 | $303.4K | -$37.8K | -14.8% |
| Summit Creek Advisors LLC | 2,170 | 0 | $314.3K | +$13.3K | 0.0% |
Top Holders by reported value
Ranked by the dollar value reported on the latest Form 13F. Share counts reflect long positions as of 2025-12-31.
| Manager | Shares | $ Value | Δ Shares | QoQ % |
|---|---|---|---|---|
| CORBYN INVESTMENT MANAGEMENT INC/MD | 15,420 | $2.2M | -80 | -0.5% |
| ISTHMUS PARTNERS, LLC | 2,832 | $410.2K | +2,832 | — |
| Summit Creek Advisors LLC | 2,170 | $314.3K | 0 | 0.0% |
| ELCO Management Co., LLC | 2,095 | $303.4K | -365 | -14.8% |
| Ancora Advisors, LLC | 247 | $35.8K | +247 | — |
New & Closed Positions this quarter
Closed Positions
0 managers exited
Top five by prior-quarter value
No managers exited their positions this quarter.
Methodology
Form 13F is the SEC's quarterly disclosure for institutional investment managers exercising discretion over $100 million or more in qualifying U.S. equity securities. Managers must file within 45 days of each calendar quarter end, which is why holdings shown here reflect a snapshot at the period date — not real-time positioning.
Quarter-over-quarter deltas compare each manager's most recently reported share count for WMS against its prior-quarter count. New positions are entries where the prior count was zero; closed positions are entries where the current count is zero. Amendments (13F-HR/A) replace prior filings for the same period.
Source: SEC EDGAR Form 13F (XML information tables). Dollar values are as reported by the manager and may use mid-quarter pricing conventions. CUSIP-to-ticker resolution is best-effort.