DUDLEY & SHANLEY, INC.
SEC Form 13F institutional filer · CIK 0000883511
13F-HR · 21 reported holdings · 2026-03-31
Reported long-US-equity value
$0.35B
Top-10 concentration
76.9%
DUDLEY & SHANLEY, INC. — $353M AUM allocation strategy
DUDLEY & SHANLEY, INC. files SEC Form 13F and reports $353M of long US equity value across 21 reported holdings for 2026-03-31.
Its largest sector bet is Financials 29.4%, followed by Industrials 28.4% and Information Technology 18.5%.
The top 10 holdings account for 77% of reported value — a conviction-weighted book concentrated in its best ideas. The sector and industry splits below are of the same reported value. Track quarter-over-quarter adds, trims, new positions and exits below — sourced from SEC 13F filings, public domain.
DUDLEY & SHANLEY, INC. — latest SEC 13F insights
Reported long-US-equity value (13F AUM)
$353M
total across 21 reported holdings · 2026-03-31 · excludes shorts, cash, non-US
Top-10 concentration
77% of value
higher = narrower conviction; lower = spread / hedging
Biggest trims (shares)
−$APH −37.2K sh · −$7.18M−$ADI −29.9K sh · −$3.64M−$ROP −15.5K sh · −$7.06M
Exited to nil (held last quarter, gone now)
None this quarter
Sector allocation (share of reported value)
each slice is a share of the reported long-US-equity value — smaller sectors and the rest of the book roll into “Other holdings”
Qtr shift = share-point change vs the prior quarter's filing — first period tracked for this filer; the column fills in with the next quarterly refresh.
Industry allocation (share of reported value)
- Transaction & Payment Processing Services10.6%—
- Life Sciences Tools & Services9.0%—
- Electronic Components8.8%—
- Semiconductors8.6%—
- Electrical Components & Equipment8.5%—
- Insurance Brokers8.1%—
- Specialty Chemicals7.9%—
- Environmental & Facilities Services6.9%—
- Other holdings31.7%—
the finer GICS cut of the same book — same denominator — smaller industries roll into “Other holdings”
Qtr shift = share-point change vs the prior quarter's filing — first period tracked for this filer; the column fills in with the next quarterly refresh.
Top S&P 500 holdings
10 of 10 rows · sorted by Value ↓
| Ticker | Holding | Shares | Value | Δ QoQ | Weight |
|---|---|---|---|---|---|
| $APH | Amphenol Corporation | 246K | $31.1M | -37.2K | 8.8% |
| $ADI | Analog Devices Inc | 95.1K | $30.3M | -29.9K | 8.6% |
| $AME | AMETEK Inc | 140K | $30M | -50 | 8.5% |
| $V | Visa Inc | 97.2K | $29.4M | -50 | 8.3% |
| $AON | Aon plc | 88.8K | $28.7M | +0 | 8.1% |
| $ECL | Ecolab Inc | 105K | $27.9M | -50 | 7.9% |
| $ROL | Rollins Inc | 456K | $24.3M | +0 | 6.9% |
| $FERG | Ferguson Enterprises Inc | 104K | $24.3M | +0 | 6.9% |
| $AWK | American Water Works Company Inc | 169K | $23M | +0 | 6.5% |
| $SCHW | Charles Schwab Corporation | 241K | $22.6M | +0 | 6.4% |
…and 11 more holdings in the full 13F filing (top positions only shown).
SEC Form 13F data sets · public domain · 45-day filing lag · >$100M AUM managers · as reported
← All 13F filers·← QuantOrb.pro
How to read Δ QoQ — the five insight categories, and the caveats
The categories. Analysts, quants and retail traders look past total portfolio value to isolate actionable signals. Five categories matter.
Conviction & concentration shifts
New positions vs complete exits — a brand-new stock signals high conviction; a full liquidation suggests a broken thesis or tax-loss harvesting. Aggressive sizing — look at share count, not dollars: a 20% share increase during a drawdown is strong dip-buying. Concentration — a narrowing top-5/10 means conviction; spreading capital across more names means hedging.
Sector & macro allocation rotations
Aggregating Δ QoQ moves across sectors shows where smart money is leaning in or sneaking out — rotating out of growth into defensives or energy, for example. The fund's total long equity exposure quarter-over-quarter is a proxy for overall institutional risk appetite.
Crowding & smart-money consensus
When several managers initiate or expand the same stock in the same quarter, that is institutional consensus. Contrarian reads: top pickers buying hard into a beaten-down name the market is selling.
Derivative & option overlays
Reported call/put changes indicate whether managers are adding downside hedges or leveraging upside exposure. Note: a long increase may be half of a market-neutral pair trade.
Who reads this
| Retail "cloners" | High-conviction ideas to replicate ~45 days after quarter-end. |
| Corporate IR | Which funds bought or dumped the stock, before the next call. |
| Quant / algo traders | Cross-sectional factor inputs: flow, momentum, ownership. |
Four caveats before you trade on it
- 45-day lag — holdings are quarter-end; positions may already be closed.
- Long-only — 13Fs miss shorts, pair trades and cash.
- No non-US / fixed income — the picture is US equities plus options.
- Corporate actions — splits and spinoffs distort raw share deltas.
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