Hudson Technologies, Inc.
US ˙ NasdaqCM ˙ US4441441098

SecurityHDSN / Hudson Technologies, Inc.
InstitutionDimensional Fund Advisors Lp
Latest Disclosed Ownership2,148,311 shares
Ownership 5.10%
Dimensional Fund Advisors Lp ownership in HDSN / Hudson Technologies, Inc.

2026-04-09 - Dimensional Fund Advisors Lp has filed an SCHEDULE 13G form with the Securities and Exchange Commission (SEC) disclosing ownership of 2,148,311 shares of Hudson Technologies, Inc. (US:HDSN). This represents 5.1 percent ownership of the company. In their previous filing dated 2020-02-12 , Dimensional Fund Advisors Lp had reported owning 384,715 shares, indicating an increase of 458.42 percent.

Institutional Ownership: 13D/G Filings

This table shows a history of the 13D/G filings made by the investor and/or investor group. Note that the share values in this table are not directly comparable to any numbers shown in the 13F table (if any).

File
Date		Effective
Date		Form Prev
Shares		 Latest
Shares		 ΔShares
(Percent)		 Ownership
(Percent)		 ΔOwnership
(Percent)
2026-04-09 2026-04-09 13G 384,715 2,148,311 458.42 5.10 466.67
2020-02-12 2020-02-12 13G/A 2,396,212 384,715 -83.94 0.90 -84.01
2019-02-08 2019-02-08 13G/A 2,355,024 2,396,212 1.75 5.63 0.54
2018-02-09 2018-02-09 13G 2,355,024 5.60

Important Note: One of the primary uses of the 13D/G filings is to evaluate the ability of a firm to control a company (ie, the "beneficial ownership"). To that end, firms are required to report not just direct holdings in companies, but indirect holdings that they control. For investment firms, these indirect holdings can include shares in funds they manage, advisory accounts, and in the case of activist campaigns, pledged votes. Therefore, share counts listed in 13D/G filings can differ significantly than share counts listed in 13F filings.

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)
2026-05-07 2026-03-31 13F HUDSON TECHNOLOGIES COM 444144109 2,148,311 105,160 5.15 12,631 -9.75 0.0006
2026-02-12 2025-12-31 13F HUDSON TECHNOLOGIES COM 444144109 2,043,151 33,670 1.68 13,996 -29.86 0.0029
2025-11-12 2025-09-30 13F HUDSON TECHNOLOGIES COM 444144109 2,009,481 2,515 0.13 19,953 22.44 0.0043
2025-08-12 2025-06-30 13F HUDSON TECHNOLOGIES COM 444144109 2,006,966 56,771 2.91 16,296 35.43 0.0038
2025-05-13 2025-03-31 13F HUDSON TECHNOLOGIES COM 444144109 1,950,195 -101,477 -4.95 12,033 5.11 0.0030
2025-02-13 2024-12-31 13F HUDSON TECHNOLOGIES COM 444144109 2,051,672 -81,592 -3.82 11,448 -35.65 0.0027
2024-11-07 2024-09-30 13F HUDSON TECHNOLOGIES COM 444144109 2,133,264 114,197 5.66 17,791 0.25 0.0043
2024-08-09 2024-06-30 13F HUDSON TECHNOLOGIES COM 444144109 2,019,067 364,117 22.00 17,747 -2.61 0.0046
2024-05-10 2024-03-31 13F HUDSON TECHNOLOGIES COM 444144109 1,654,950 80,181 5.09 18,221 -14.22 0.0049
2024-02-07 2023-12-31 13F HUDSON TECHNOLOGIES COM 444144109 1,574,769 30,217 1.96 21,243 3.40 0.0062
2023-11-09 2023-09-30 13F HUDSON TECHNOLOGIES COM 444144109 1,544,552 128,308 9.06 20,543 50.77 0.0067
2023-08-09 2023-06-30 13F HUDSON TECHNOLOGIES COM 444144109 1,416,244 137,453 10.75 13,625 22.06 0.0043
2023-05-12 2023-03-31 13F HUDSON TECHNOLOGIES COM 444144109 1,278,791 173,622 15.71 11,164 101,381.82 0.0038
2023-02-09 2022-12-31 13F HUDSON TECHNOLOGIES COM 444144109 1,105,169 145,633 15.18 11 -99.84 0.0033
2022-11-10 2022-09-30 13F HUDSON TECHNOLOGIES COM 444144109 959,536 271,227 39.40 7,052 36.43 0.0027
2022-08-12 2022-06-30 13F HUDSON TECHNOLOGIES COM 444144109 688,309 185,821 36.98 5,169 65.67 0.0019
2022-05-13 2022-03-31 13F HUDSON TECHNOLOGIES COM 444144109 502,488 165,015 48.90 3,120 108.28 0.0010
2022-02-09 2021-12-31 13F HUDSON TECHNOLOGIES COM 444144109 337,473 64,123 23.46 1,498 55.23 0.0005
2021-11-12 2021-09-30 13F HUDSON TECHNOLOGIES COM 444144109 273,350 95,518 53.71 965 59.50 0.0003
2021-08-12 2021-06-30 13F HUDSON TECHNOLOGIES COM 444144109 177,832 177,832 605 0.0002
2020-05-14 2020-03-31 13F HUDSON TECHNOLOGIES COM 444144109 0 -384,715 -100.00 0 -100.00
2020-02-14 2019-12-31 13F HUDSON TECHNOLOGIES COM 444144109 384,715 -999,670 -72.21 376 -61.75 0.0001
2019-11-12 2019-09-30 13F HUDSON TECHNOLOGIES COM 444144109 1,384,385 -922,652 -39.99 983 -50.45 0.0004
2019-08-13 2019-06-30 13F HUDSON TECHNOLOGIES COM 444144109 2,307,037 -44,757 -1.90 1,984 -56.29 0.0008
2019-08-12 2019-03-31 13F/A-2 HUDSON TECHNOLOGIES COM 444144109 2,351,794 -44,418 -1.85 4,539 112.80 0.0018
2019-05-10 2019-03-31 13F HUDSON TECHNOLOGIES COM 444144109 2,351,794 -44,418 4,539
2019-02-26 2018-12-31 13F/A-1 HUDSON TECHNOLOGIES COM 444144109 2,396,212 -87,956 -3.54 2,133 -32.92 0.0010
2019-02-13 2018-12-31 13F HUDSON TECHNOLOGIES COM 444144109 2,396,212 -87,956 2,133
2018-11-13 2018-09-30 13F HUDSON TECHNOLOGIES COM 444144109 2,484,168 -204,117 -7.59 3,180 -41.14 0.0012
2018-08-10 2018-06-30 13F HUDSON TECHNOLOGIES COM 444144109 2,688,285 294,053 12.28 5,403 -54.32 0.0022
2018-05-11 2018-03-31 13F HUDSON TECHNOLOGIES COM 444144109 2,394,232 39,208 1.66 11,828 -17.26 0.0049
2018-02-12 2017-12-31 13F HUDSON TECHNOLOGIES COM 444144109 2,355,024 303,789 14.81 14,295 -10.77 0.0059
2017-11-13 2017-09-30 13F HUDSON TECHNOLOGIES COM 444144109 2,051,235 340,455 19.90 16,020 10.82 0.0070
2017-08-11 2017-06-30 13F HUDSON TECHNOLOGIES COM 444144109 1,710,780 267,862 18.56 14,456 51.80 0.0067
2017-05-12 2017-03-31 13F HUDSON TECHNOLOGIES COM 444144109 1,442,918 363,346 33.66 9,523 10.13 0.0046
2017-02-09 2016-12-31 13F HUDSON TECHNOLOGIES COM 444144109 1,079,572 366,756 51.45 8,647 82.43 0.0043
2016-11-10 2016-09-30 13F HUDSON TECHNOLOGIES COM 444144109 712,816 237,118 49.85 4,740 176.71 0.0026
2016-08-09 2016-06-30 13F HUDSON TECHNOLOGIES COM 444144109 475,698 30,082 6.75 1,713 17.17 0.0010
2016-05-13 2016-03-31 13F HUDSON TECHNOLOGIES COM 444144109 445,616 3,672 0.83 1,462 11.35 0.0009
2016-02-10 2015-12-31 13F HUDSON TECHNOLOGIES COM 444144109 441,944 0 0.00 1,313 0.00 0.0008
2015-11-13 2015-09-30 13F HUDSON TECHNOLOGIES COM 444144109 441,944 398,647 920.73 1,313 769.54 0.0009
2015-08-14 2015-06-30 13F HUDSON TECHNOLOGIES COM 444144109 43,297 0 0.00 151 -16.57 0.0001
2015-05-14 2015-03-31 13F HUDSON TECHNOLOGIES COM 444144109 43,297 0 0.00 181 11.04 0.0001
2015-02-06 2014-12-31 13F HUDSON TECHNOLOGIES COM 444144109 43,297 0 0.00 163 13.99 0.0001
2014-11-13 2014-09-30 13F HUDSON TECHNOLOGIES COM 444144109 43,297 0 0.00 143 14.40 0.0001
2014-08-08 2014-06-30 13F HUDSON TECHNOLOGIES COM 444144109 43,297 0 0.00 125 3.31 0.0001
2014-05-14 2014-03-31 13F HUDSON TECHNOLOGIES COM 444144109 43,297 0 0.00 121 -24.37 0.0001
2014-02-12 2013-12-31 13F HUDSON TECHNOLOGIES COM 444144109 43,297 0 0.00 160 81.82 0.0001
2013-11-13 2013-09-30 13F HUDSON TECHNOLOGIES COM 444144109 43,297 -4,902 -10.17 88 -42.86 0.0001
2013-08-15 2013-06-30 13F HUDSON TECHNOLOGIES COM 444144109 48,199 48,199 154 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.