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

SecurityGLDD / Great Lakes Dredge & Dock Corporation
InstitutionSimplex Trading, Llc
Latest Disclosed Ownership0 shares
Latest Disclosed Value $ 0
Simplex Trading, Llc ownership in GLDD / Great Lakes Dredge & Dock Corporation

On August 5, 2025 - Simplex Trading, Llc filed a 13F-HR form disclosing ownership of 0 shares of Great Lakes Dredge & Dock Corporation (US:GLDD) valued at $0 USD as of June 30, 2025. The entity filed a previous 13F-HR on May 12, 2025 disclosing 17,349 shares of Great Lakes Dredge & Dock Corporation. The current value of the position is $0 USD.

Simplex Trading, Llc has a history of taking positions in derivatives of the underlying security (GLDD) in the form of stock options. The firm currently holds call options representing 21,400 of underlying shares valued at $363,800 USD and put options representing 1,100 of underlying shares valued at $18,700 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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 .

Institutional Put/Call Ratios
(Premium Subscription Required)

In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

GLDD / Great Lakes Dredge & Dock Corporation Historical Put/Call Ratio
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)
2025-08-05 2025-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 0 -17,349 -100.00 0 0.0000
2025-05-12 2025-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 17,349 17,349 0 0.0001
2024-04-25 2024-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 0 -22,533 -100.00 0 0.0000
2024-02-02 2023-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 22,533 -181 -0.80 0 0.0001
2023-11-01 2023-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 22,714 22,714 0 0.0001
2023-08-04 2023-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 0 -1,159 -100.00 0 0.0000
2023-04-27 2023-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 1,159 -1,414 -54.96 0 0.0000
2023-02-02 2022-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 2,573 2,573 0 0.0000
2022-11-04 2022-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 0 -11,084 -100.00 0 -100.00
2022-08-03 2022-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 11,084 7,746 232.06 145 215.22 0.0002
2022-05-02 2022-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 3,338 -5,342 -61.54 46 -66.18 0.0000
2022-02-23 2021-12-31 13F/A-1 GREAT LAKES DREDGE & DOCK COM 390607109 8,680 787 9.97 136 18.26 0.0001
2022-02-04 2021-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 7,893 0 115 0.0000
2021-10-28 2021-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 7,893 -900 -10.24 115 -10.16 0.0001
2021-08-12 2021-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 8,793 3,941 81.22 128 0.0001
2021-04-26 2021-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 4,852 4,852 -44.82 0 -100.00 0.0000
2020-10-14 2020-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 0 -15,845 -100.00 0 -100.00
2020-07-13 2020-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 15,845 -25,948 -62.09 146 -57.80 0.0002
2020-04-29 2020-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 41,793 41,793 346 0.0006
2019-10-15 2019-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 0 -1,488 -100.00 0 -100.00
2019-07-26 2019-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 1,488 1,488 16 0.0000
2019-04-18 2019-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 0 -10,440 -100.00 0 -100.00
2019-01-16 2018-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 10,440 -6,885 -39.74 69 -35.51 0.0002
2018-10-23 2018-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 17,325 -6,803 -28.20 107 -15.08 0.0003
2018-07-30 2018-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 24,128 -4,775 -16.52 126 -4.55 0.0005
2018-04-26 2018-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 28,903 28,903 19.79 132 4.76 0.0058
2018-01-10 2017-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 0 -420 -100.00 0 -100.00
2017-10-25 2017-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 420 420 2 0.0001
2017-04-21 2017-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 0 -12,027 -100.00 0 -100.00
2017-01-11 2016-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 12,027 12,027 50 0.0030
2016-10-07 2016-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 0 -3,292 -100.00 0 -100.00
2016-07-18 2016-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 3,292 3,292 0.00 14 0.0009
2016-01-20 2015-12-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 0 -34 -100.00 0 -100.00 0.0000
2015-10-08 2015-09-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 34 -467 -93.21 0 -100.00
2015-07-08 2015-06-30 13F GREAT LAKES DREDGE & DOCK COM 390607109 501 -132 -20.85 2 -33.33 0.0002
2015-04-21 2015-03-31 13F GREAT LAKES DREDGE & DOCK COM 390607109 633 633 3 0.0003
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-14 2026-03-31 13F GREAT LAKES DREDGE & DOCK CALL Call 21,400 364 n/a n/a n/a
2026-02-11 2025-12-31 13F GREAT LAKES DREDGE & DOCK CALL Call 0 -100.00 0 n/a n/a n/a
2025-11-12 2025-09-30 13F GREAT LAKES DREDGE & DOCK CALL Call 66,600 -12.94 1 n/a n/a n/a
2025-08-05 2025-06-30 13F GREAT LAKES DREDGE & DOCK CALL Call 76,500 1 n/a n/a n/a
2025-05-12 2025-03-31 13F GREAT LAKES DREDGE & DOCK CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-02-11 2024-12-31 13F GREAT LAKES DREDGE & DOCK CALL Call 252,200 532.08 3 n/a n/a n/a
2024-11-08 2024-09-30 13F GREAT LAKES DREDGE & DOCK CALL Call 39,900 -18.57 0 n/a n/a n/a
2024-07-25 2024-06-30 13F GREAT LAKES DREDGE & DOCK CALL Call 49,000 -29.29 0 n/a n/a n/a
2024-04-25 2024-03-31 13F GREAT LAKES DREDGE & DOCK CALL Call 69,300 72.82 1 n/a n/a n/a
2024-02-02 2023-12-31 13F GREAT LAKES DREDGE & DOCK CALL Call 40,100 102.53 0 n/a n/a n/a
2023-11-01 2023-09-30 13F GREAT LAKES DREDGE & DOCK CALL Call 19,800 371.43 0 n/a n/a n/a
2023-08-04 2023-06-30 13F GREAT LAKES DREDGE & DOCK CALL Call 4,200 4,100.00 0 n/a n/a n/a
2023-04-27 2023-03-31 13F GREAT LAKES DREDGE & DOCK CALL Call 100 -66.67 0 n/a n/a n/a
2023-02-02 2022-12-31 13F GREAT LAKES DREDGE & DOCK CALL Call 300 0 n/a n/a n/a
2022-08-03 2022-06-30 13F GREAT LAKES DREDGE & DOCK CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2022-05-02 2022-03-31 13F GREAT LAKES DREDGE & DOCK CALL Call 300 -50.00 4 -50.00 n/a n/a n/a
2022-02-04 2021-12-31 13F GREAT LAKES DREDGE & DOCK CALL Call 600 0.00 8 0.00 n/a n/a n/a
2021-10-28 2021-09-30 13F GREAT LAKES DREDGE & DOCK CALL Call 600 0.00 8 0.00 n/a n/a n/a
2021-08-12 2021-06-30 13F GREAT LAKES DREDGE & DOCK CALL Call 600 7,400.00 8 n/a n/a n/a
2021-04-26 2021-03-31 13F GREAT LAKES DREDGE & DOCK CALL Call 8 -98.56 0 -100.00 n/a n/a n/a
2021-02-02 2020-12-31 13F GREAT LAKES DREDGE & DOCK CALL Call 554 98.57 729 175.09 n/a n/a n/a
2020-10-14 2020-09-30 13F GREAT LAKES DREDGE & DOCK CALL Call 279 771.88 265 813.79 n/a n/a n/a
2020-07-13 2020-06-30 13F GREAT LAKES DREDGE & DOCK CALL Call 32 -31.91 29 -25.64 n/a n/a n/a
2020-04-29 2020-03-31 13F GREAT LAKES DREDGE & DOCK CALL Call 47 -74.46 39 -81.25 n/a n/a n/a
2020-02-05 2019-12-31 13F GREAT LAKES DREDGE & DOCK CALL Call 184 283.33 208 316.00 n/a n/a n/a
2019-10-15 2019-09-30 13F GREAT LAKES DREDGE & DOCK CALL Call 48 585.71 50 614.29 n/a n/a n/a
2019-07-26 2019-06-30 13F GREAT LAKES DREDGE & DOCK CALL Call 7 -87.50 7 -85.71 n/a n/a n/a
2019-04-18 2019-03-31 13F GREAT LAKES DREDGE & DOCK CALL Call 56 2,700.00 49 4,800.00 n/a n/a n/a
2019-01-16 2018-12-31 13F GREAT LAKES DREDGE & DOCK CALL Call 2 -97.94 1 -98.33 n/a n/a n/a
2018-10-23 2018-09-30 13F GREAT LAKES DREDGE & DOCK CALL Call 97 -17.09 60 -1.64 n/a n/a n/a
2018-07-30 2018-06-30 13F GREAT LAKES DREDGE & DOCK CALL Call 117 20.62 61 1.67 n/a n/a n/a
2018-04-26 2018-03-31 13F GREAT LAKES DREDGE & DOCK CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2018-01-10 2017-12-31 13F GREAT LAKES DREDGE & DOCK CALL Call 186 -38.21 11 -8.33 n/a n/a n/a
2017-10-25 2017-09-30 13F GREAT LAKES DREDGE & DOCK CALL Call 301 61.83 12 9.09 n/a n/a n/a
2017-04-21 2017-03-31 13F GREAT LAKES DREDGE & DOCK CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2017-01-11 2016-12-31 13F GREAT LAKES DREDGE & DOCK CALL Call 142 0 n/a n/a n/a
2016-10-07 2016-09-30 13F GREAT LAKES DREDGE & DOCK CALL Call 0 -100.00 0 n/a n/a n/a
2016-07-18 2016-06-30 13F GREAT LAKES DREDGE & DOCK CALL Call 50 0 n/a n/a n/a
2015-04-21 2015-03-31 13F GREAT LAKES DREDGE & DOCK CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2015-03-04 2014-12-31 13F GREAT LAKES DREDGE & DOCK CALL Call 93 33 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-14 2026-03-31 13F GREAT LAKES DREDGE & DOCK PUT Put 1,100 19 n/a n/a n/a
2026-02-11 2025-12-31 13F GREAT LAKES DREDGE & DOCK PUT Put 0 -100.00 0 n/a n/a n/a
2025-11-12 2025-09-30 13F GREAT LAKES DREDGE & DOCK PUT Put 3,400 750.00 0 n/a n/a n/a
2025-08-05 2025-06-30 13F GREAT LAKES DREDGE & DOCK PUT Put 400 -20.00 0 n/a n/a n/a
2025-05-12 2025-03-31 13F GREAT LAKES DREDGE & DOCK PUT Put 500 -37.50 0 n/a n/a n/a
2025-02-11 2024-12-31 13F GREAT LAKES DREDGE & DOCK PUT Put 800 -20.00 0 n/a n/a n/a
2024-11-08 2024-09-30 13F GREAT LAKES DREDGE & DOCK PUT Put 1,000 233.33 0 n/a n/a n/a
2024-07-25 2024-06-30 13F GREAT LAKES DREDGE & DOCK PUT Put 300 50.00 0 n/a n/a n/a
2024-04-25 2024-03-31 13F GREAT LAKES DREDGE & DOCK PUT Put 200 -83.33 0 n/a n/a n/a
2024-02-02 2023-12-31 13F GREAT LAKES DREDGE & DOCK PUT Put 1,200 -50.00 0 n/a n/a n/a
2023-11-01 2023-09-30 13F GREAT LAKES DREDGE & DOCK PUT Put 2,400 0.00 0 n/a n/a n/a
2023-08-04 2023-06-30 13F GREAT LAKES DREDGE & DOCK PUT Put 2,400 0 n/a n/a n/a
2023-04-27 2023-03-31 13F GREAT LAKES DREDGE & DOCK PUT Put 0 -100.00 0 n/a n/a n/a
2023-02-02 2022-12-31 13F GREAT LAKES DREDGE & DOCK PUT Put 500 0 n/a n/a n/a
2022-11-04 2022-09-30 13F GREAT LAKES DREDGE & DOCK PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-08-03 2022-06-30 13F GREAT LAKES DREDGE & DOCK PUT Put 15,000 177.78 196 161.33 n/a n/a n/a
2022-05-02 2022-03-31 13F GREAT LAKES DREDGE & DOCK PUT Put 5,400 -16.92 75 -26.47 n/a n/a n/a
2022-02-23 2021-12-31 13F/A GREAT LAKES DREDGE & DOCK PUT Put 6,500 -65.79 102 -63.18 n/a n/a n/a
2022-02-04 2021-12-31 13F GREAT LAKES DREDGE & DOCK PUT Put 19,000 277 n/a n/a n/a
2021-10-28 2021-09-30 13F GREAT LAKES DREDGE & DOCK PUT Put 19,000 0.00 277 0.00 n/a n/a n/a
2021-08-12 2021-06-30 13F GREAT LAKES DREDGE & DOCK PUT Put 19,000 949,900.00 277 n/a n/a n/a
2021-04-26 2021-03-31 13F GREAT LAKES DREDGE & DOCK PUT Put 2 -97.22 0 -100.00 n/a n/a n/a
2021-02-02 2020-12-31 13F GREAT LAKES DREDGE & DOCK PUT Put 72 111.76 94 193.75 n/a n/a n/a
2020-10-14 2020-09-30 13F GREAT LAKES DREDGE & DOCK PUT Put 34 -87.68 32 -87.45 n/a n/a n/a
2020-07-13 2020-06-30 13F GREAT LAKES DREDGE & DOCK PUT Put 276 -53.22 255 -47.85 n/a n/a n/a
2020-04-29 2020-03-31 13F GREAT LAKES DREDGE & DOCK PUT Put 590 391.67 489 262.22 n/a n/a n/a
2020-02-05 2019-12-31 13F GREAT LAKES DREDGE & DOCK PUT Put 120 3,900.00 135 4,400.00 n/a n/a n/a
2019-10-15 2019-09-30 13F GREAT LAKES DREDGE & DOCK PUT Put 3 -89.29 3 -90.00 n/a n/a n/a
2019-07-26 2019-06-30 13F GREAT LAKES DREDGE & DOCK PUT Put 28 833.33 30 900.00 n/a n/a n/a
2018-07-30 2018-06-30 13F GREAT LAKES DREDGE & DOCK PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2018-04-26 2018-03-31 13F GREAT LAKES DREDGE & DOCK PUT Put 80 4 n/a n/a n/a
2018-01-10 2017-12-31 13F GREAT LAKES DREDGE & DOCK PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2017-10-25 2017-09-30 13F GREAT LAKES DREDGE & DOCK PUT Put 12 0 n/a n/a n/a
2017-04-21 2017-03-31 13F GREAT LAKES DREDGE & DOCK PUT Put 0 -100.00 0 n/a n/a n/a
2017-01-11 2016-12-31 13F GREAT LAKES DREDGE & DOCK PUT Put 25 0 n/a n/a n/a
2016-10-07 2016-09-30 13F GREAT LAKES DREDGE & DOCK PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2016-07-18 2016-06-30 13F GREAT LAKES DREDGE & DOCK PUT Put 49 3 n/a n/a n/a
2015-10-08 2015-09-30 13F GREAT LAKES DREDGE & DOCK PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2015-07-08 2015-06-30 13F GREAT LAKES DREDGE & DOCK PUT Put 4 -20.00 0 -100.00 n/a n/a n/a
2015-04-21 2015-03-31 13F GREAT LAKES DREDGE & DOCK PUT Put 5 1 n/a n/a n/a
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.