Great Lakes Dredge & Dock Corporation
US ˙ NasdaqGS ˙ US3906071093
DETTE SYMBOL ER IKKE LÆNGERE AKTIVT

SecurityGLDD / Great Lakes Dredge & Dock Corporation
InstitutionMarshall Wace, Llp
Latest Disclosed Ownership52,085 shares
Latest Disclosed Value $ 885,445
Marshall Wace, Llp ownership in GLDD / Great Lakes Dredge & Dock Corporation

On May 14, 2026 - Marshall Wace, Llp filed a 13F-HR form disclosing ownership of 52,085 shares of Great Lakes Dredge & Dock Corporation (US:GLDD) valued at $885,445 USD as of March 31, 2026. The entity filed a previous 13F-HR on May 15, 2025 disclosing 0 shares of Great Lakes Dredge & Dock Corporation. The current value of the position is $885,445 USD.

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)
2026-05-14 2026-03-31 13F GREAT LAKES DRED COMMON STOCK 390607109 52,085 52,085 885 0.0004
2025-05-15 2025-03-31 13F GREAT LAKES DRED COMMON STOCK 390607109 0 -92,197 -100.00 0 -100.00
2025-02-13 2024-12-31 13F GREAT LAKES DRED COMMON STOCK 390607109 92,197 -165,940 -64.28 1,041 -61.74 0.0013
2024-11-14 2024-09-30 13F GREAT LAKES DRED COMMON STOCK 390607109 258,137 50,511 24.33 2,718 49.18 0.0033
2024-08-14 2024-06-30 13F GREAT LAKES DRED COMMON STOCK 390607109 207,626 207,626 1,823 0.0024
2024-05-15 2024-03-31 13F GREAT LAKES DRED COMMON STOCK 390607109 0 -98,464 -100.00 0 -100.00
2024-02-14 2023-12-31 13F GREAT LAKES DRED COMMON STOCK 390607109 98,464 -67,732 -40.75 756 -42.90 0.0013
2023-11-14 2023-09-30 13F GREAT LAKES DRED COMMON STOCK 390607109 166,196 122,655 281.70 1,325 272.96 0.0027
2023-08-14 2023-06-30 13F GREAT LAKES DRED COMMON STOCK 390607109 43,541 -149,504 -77.45 355 -66.13 0.0007
2023-05-15 2023-03-31 13F GREAT LAKES DRED COMMON STOCK 390607109 193,045 167,308 650.07 1,048 584.97 0.0022
2023-02-14 2022-12-31 13F GREAT LAKES DRED COMMON STOCK 390607109 25,737 25,737 153 0.0003
2020-08-13 2020-06-30 13F GREAT LAKES DRED COMMON STOCK 390607109 0 -91,100 -100.00 0 -100.00
2020-05-15 2020-03-31 13F GREAT LAKES DRED COMMON STOCK 390607109 91,100 90,055 8,617.70 756 6,200.00 0.0076
2020-02-14 2019-12-31 13F GREAT LAKES DRED COMMON STOCK 390607109 1,045 1,045 12 0.0001
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.