Westlake Corporation
US ˙ NYSE ˙ US9604131022

SecurityWLK / Westlake Corporation
InstitutionAmalgamated Bank
Latest Disclosed Ownership15,006 shares
Latest Disclosed Value $ 1,753
Amalgamated Bank reports 0.26% decrease in ownership of WLK / Westlake Corporation

On May 8, 2026 - Amalgamated Bank filed a 13F-HR form disclosing ownership of 15,006 shares of Westlake Corporation (US:WLK) valued at $1,753,001 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 5, 2026 disclosing 15,045 shares of Westlake Corporation. This represents a change in shares of -0.26% during the quarter. The current value of the position is $1,296,368 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)
2026-05-08 2026-03-31 13F WESTLAKE CORPORATION COM COM 960413102 15,006 -39 -0.26 2 0.00 0.0134
2026-02-05 2025-12-31 13F WESTLAKE CORPORATION COM COM 960413102 15,045 -257 -1.68 1 0.00 0.0080
2025-10-29 2025-09-30 13F WESTLAKE CORPORATION COM COM 960413102 15,302 64 0.42 1 0.00 0.0084
2025-08-04 2025-06-30 13F WESTLAKE CORPORATION COM COM 960413102 15,238 -337 -2.16 1 0.00 0.0089
2025-04-25 2025-03-31 13F WESTLAKE CORPORATION COM COM 960413102 15,575 -107 -0.68 2 0.00 0.0133
2025-02-04 2024-12-31 13F WESTLAKE CORPORATION COM COM 960413102 15,682 0 0.00 2 -50.00 0.0148
2024-10-30 2024-09-30 13F WESTLAKE CORPORATION COM COM 960413102 15,682 -618 -3.79 2 0.00 0.0194
2024-08-12 2024-06-30 13F WESTLAKE CORPORATION COM COM 960413102 16,300 -5,549 -25.40 2 -33.33 0.0201
2024-04-23 2024-03-31 13F WESTLAKE CORPORATION COM COM 960413102 21,849 -37 -0.17 3 0.00 0.0286
2024-02-06 2023-12-31 13F WESTLAKE CORPORATION COM COM 960413102 21,886 1,030 4.94 3 50.00 0.0244
2023-11-08 2023-09-30 13F WESTLAKE CORPORATION COM COM 960413102 20,856 32 0.15 3 0.00 0.0221
2023-08-11 2023-06-30 13F WESTLAKE CORPORATION COM COM 960413102 20,824 -1,337 -6.03 2 0.00 0.0201
2023-05-02 2023-03-31 13F WESTLAKE CORPORATION COM COM 960413102 22,161 -3,582 -13.91 3 0.00 0.0219
2023-02-10 2022-12-31 13F WESTLAKE CORPORATION COM COM 960413102 25,743 21,855 562.11 3 -99.41 0.0235
2022-11-09 2022-09-30 13F WESTLAKE CORPORATION COM COM 960413102 3,888 -2,438 -38.54 338 -45.48 0.0033
2022-08-15 2022-06-30 13F WESTLAKE CORPORATION COM COM 960413102 6,326 -46 -0.72 620 -21.12 0.0058
2022-08-25 2022-03-31 13F/A-1 WESTLAKE CORPORATION COM COM 960413102 6,372 58 0.92 786 28.22 0.0061
2022-06-30 2022-03-31 13F WESTLAKE CORPORATION COM COM 960413102 6,372 58 786 0.0062
2022-02-15 2021-12-31 13F/A-1 WESTLAKE CHEMICAL COM 960413102 6,314 -2,280 -26.53 613 -21.71 0.0045
2022-02-15 2021-12-31 13F WESTLAKE CHEMICAL COM 960413102 6,314 -2,280 613 0.0045
2021-10-29 2021-09-30 13F WESTLAKE CHEMICAL COM 960413102 8,594 -332 -3.72 783 -2.61 0.0066
2021-08-16 2021-06-30 13F WESTLAKE CHEMICAL COM 960413102 8,926 4,989 126.72 804 129.71 0.0064
2021-05-13 2021-03-31 13F WESTLAKE CHEMICAL COM 960413102 3,937 -278 -6.60 350 1.74 0.0131
2021-02-12 2020-12-31 13F WESTLAKE CHEMICAL COM 960413102 4,215 -14 -0.33 344 28.84 0.0130
2020-10-30 2020-09-30 13F WESTLAKE CHEMICAL COM 960413102 4,229 4 0.09 267 17.62 0.0116
2020-08-10 2020-06-30 13F WESTLAKE CHEMICAL COM 960413102 4,225 -3,469 -45.09 227 -22.79 0.0105
2020-05-13 2020-03-31 13F WESTLAKE CHEMICAL COM 960413102 7,694 -211 -2.67 294 -47.03 0.0072
2020-02-13 2019-12-31 13F WESTLAKE CHEMICAL COM 960413102 7,905 923 13.22 555 21.44 0.0102
2019-11-13 2019-09-30 13F WESTLAKE CHEMICAL COM 960413102 6,982 -84 -1.19 457 -6.92 0.0096
2019-08-14 2019-06-30 13F WESTLAKE CHEMICAL COM 960413102 7,066 2,154 43.85 491 47.45 0.0115
2019-05-15 2019-03-31 13F WESTLAKE CHEMICAL COM 960413102 4,912 147 3.08 333 5.71 0.0081
2019-02-15 2018-12-31 13F WESTLAKE CHEMICAL COM 960413102 4,765 -169 -3.43 315 -23.17 0.0089
2018-11-14 2018-09-30 13F WESTLAKE CHEMICAL COM 960413102 4,934 -102 -2.03 410 -24.35 0.0101
2018-07-18 2018-06-30 13F WESTLAKE CHEMICAL COM 960413102 5,036 -2,155 -29.97 542 -32.17 0.0132
2018-05-22 2018-03-31 13F WESTLAKE CHEMICAL COM 960413102 7,191 219 3.14 799 7.54 0.0212
2018-02-13 2017-12-31 13F WESTLAKE CHEMICAL COM 960413102 6,972 400 6.09 743 36.08 0.0201
2017-11-09 2017-09-30 13F WESTLAKE CHEMICAL COM 960413102 6,572 -36 -0.54 546 24.66 0.0170
2017-08-10 2017-06-30 13F WESTLAKE CHEMICAL COM 960413102 6,608 1,163 21.36 438 21.67 0.0144
2017-05-12 2017-03-31 13F WESTLAKE CHEMICAL COM 960413102 5,445 177 3.36 360 22.03 0.0179
2017-02-14 2016-12-31 13F WESTLAKE CHEMICAL COM 960413102 5,268 672 14.62 295 19.92 0.0133
2016-11-15 2016-09-30 13F/A-1 WESTLAKE CHEMICAL COM 960413102 4,596 13 0.28 246 9.82 0.0143
2016-08-16 2016-06-30 13F WESTLAKE CHEMICAL COM 960413102 4,583 500 12.25 224 -17.04 0.0130
2014-05-12 2014-03-31 13F WESTLAKE CHEM COM 960413102 4,083 2,025 98.40 270 7.57 0.0465
2014-02-13 2013-12-31 13F WESTLAKE CHEM COM 960413102 2,058 2,058 251 0.0427
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.