Great Lakes Dredge & Dock Corporation
US ˙ NasdaqGS ˙ US3906071093
DIESES SYMBOL IST NICHT MEHR AKTIV

SecurityGLDD / Great Lakes Dredge & Dock Corporation
InstitutionSei Investments Co
Latest Disclosed Ownership54,243 shares
Latest Disclosed Value $ 711,662
Sei Investments Co ownership in GLDD / Great Lakes Dredge & Dock Corporation

On February 13, 2026 - Sei Investments Co filed a 13F-HR form disclosing ownership of 54,243 shares of Great Lakes Dredge & Dock Corporation (US:GLDD) valued at $711,668 USD as of December 31, 2025. The entity filed a previous 13F-HR on May 12, 2023 disclosing 0 shares of Great Lakes Dredge & Dock Corporation. The current value of the position is $922,131 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.

Upgrade to unlock premium data and export to Excel .

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)
2026-02-13 2025-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 54,243 54,243 712
2023-05-12 2023-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 0 -348,772 -100.00 0 -100.00
2023-02-10 2022-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 348,772 1,478 0.43 2,075 -21.16 0.0046
2022-11-14 2022-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 347,294 225,518 185.19 2,632 64.91 0.0059
2022-08-15 2022-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 121,776 -7,219 -5.60 1,596 -11.82 0.0034
2022-05-13 2022-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 128,995 -3,400 -2.57 1,810 -13.02 0.0036
2022-02-14 2021-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 132,395 97,112 275.24 2,081 291.17 0.0039
2021-11-12 2021-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 35,283 -4,020 -10.23 532 -7.32 0.0011
2021-08-06 2021-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 39,303 -25,291 -39.15 574 -36.85 0.0013
2021-05-12 2021-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 64,594 -104,528 -61.81 909 -59.18 0.0023
2021-02-08 2020-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 169,122 -14,549 -7.92 2,227 27.48 0.0058
2020-12-04 2020-09-30 13F/A-1 GREAT LAKES DREDGE & DOCK COM 390607109 183,671 -7,743 -4.05 1,747 -1.41 0.0051
2020-11-06 2020-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 183,671 -7,743 1,747 4,206.3876
2020-08-17 2020-06-30 13F/A-1 GREAT LAKES DREDGE & DOCK COM 390607109 191,414 -18,249 -8.70 1,772 1.90 0.0055
2020-08-11 2020-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 191,414 -18,249 2,122 5,756.0380
2020-05-14 2020-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 209,663 -4,184 -1.96 1,739 -28.20 0.0064
2020-02-06 2019-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 213,847 -756 -0.35 2,422 8.61 0.0072
2019-11-12 2019-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 214,603 11,863 5.85 2,230 0.04 0.0057
2019-08-14 2019-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 202,740 159,726 371.33 2,229 491.25 0.0073
2019-05-15 2019-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 43,014 25,742 149.04 377 249.07 0.0013
2019-02-13 2018-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 17,272 17,272 108 0.0004
2016-05-10 2016-03-31 13F/A-1 GREAT LAKES DREDGE & DOCK COM 390607109 0 -4,338 -100.00 0 -100.00
2016-02-03 2015-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 4,338 -23,401 -84.36 17 -87.86 0.0001
2015-11-02 2015-09-30 13F/A-1 GREAT LAKES DREDGE & DOCK COM 390607109 27,739 -596 -2.10 140 -17.16 0.0013
2015-10-30 2015-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 27,739 140
2015-08-07 2015-06-30 13F/A-1 GREAT LAKES DREDGE & DOCK COM 390607109 28,335 683 2.47 169 1.81 0.0015
2015-08-04 2015-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 28,335 683 169 0.0015
2015-05-14 2015-03-31 13F/A-1 GREAT LAKES DREDGE & DOCK COM 390607109 27,652 12,487 82.34 166 27.69 0.0014
2015-05-01 2015-03-31 13F GREAT BASIN SCIENTIFIC UNIT 99/99/9999 390607109 27,652 166
2015-02-10 2014-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 15,165 15,165 130 0.0011
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.