Westlake Corporation
US ˙ NYSE ˙ US9604131022

SecurityWLK / Westlake Corporation
InstitutionParallel Advisors, LLC
Latest Disclosed Ownership355 shares
Latest Disclosed Value $ 26,249
Parallel Advisors, LLC reports 54.37% decrease in ownership of WLK / Westlake Corporation

On February 11, 2026 - Parallel Advisors, LLC filed a 13F-HR form disclosing ownership of 355 shares of Westlake Corporation (US:WLK) valued at $26,249 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 13, 2025 disclosing 778 shares of Westlake Corporation. This represents a change in shares of -54.37% during the quarter. The current value of the position is $30,668 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)
2026-02-11 2025-12-31 13F WESTLAKE CORPORATION COM Stock 960413102 355 -423 -54.37 26 -55.93 0.0005
2025-11-13 2025-09-30 13F WESTLAKE CORPORATION COM Stock 960413102 778 286 58.13 60 59.46 0.0011
2025-07-08 2025-06-30 13F WESTLAKE CORPORATION COM Stock 960413102 492 -33 -6.29 37 -28.85 0.0007
2025-04-08 2025-03-31 13F WESTLAKE CORPORATION COM Stock 960413102 525 133 33.93 53 18.18 0.0012
2025-02-10 2024-12-31 13F WESTLAKE CORPORATION COM Stock 960413102 392 -162 -29.24 45 -46.99 0.0010
2024-11-13 2024-09-30 13F WESTLAKE CORPORATION COM Stock 960413102 554 153 38.15 83 43.10 0.0020
2024-08-08 2024-06-30 13F WESTLAKE CORPORATION COM Stock 960413102 401 48 13.60 58 9.43 0.0015
2024-05-06 2024-03-31 13F WESTLAKE CORPORATION COM Stock 960413102 353 61 20.89 54 32.50 0.0015
2024-02-12 2023-12-31 13F WESTLAKE CORPORATION COM Stock 960413102 292 -166 -36.24 41 -29.82 0.0012
2024-05-20 2023-09-30 13F/A-1 WESTLAKE CORPORATION COM Stock 960413102 458 4 0.88 57 5.56 0.0019
2023-11-14 2023-09-30 13F WESTLAKE CORPORATION COM Stock 960413102 458 4 57 0.0019
2024-05-20 2023-06-30 13F/A-1 WESTLAKE CORPORATION COM Stock 960413102 454 11 2.48 54 5.88 0.0017
2023-08-04 2023-06-30 13F WESTLAKE CORPORATION COM Stock 960413102 454 11 54 0.0017
2024-05-20 2023-03-31 13F/A-1 WESTLAKE CORPORATION COM Stock 960413102 443 -1 -0.23 51 13.33 0.0017
2023-04-25 2023-03-31 13F WESTLAKE CORPORATION COM Stock 960413102 443 -1 51 0.0017
2023-02-06 2022-12-31 13F WESTLAKE CORPORATION COM Stock 960413102 444 37 9.09 46 28.57 0.0020
2022-11-10 2022-09-30 13F WESTLAKE CORPORATION COM Stock 960413102 407 -66 -13.95 35 -23.91 0.0016
2022-08-01 2022-06-30 13F WESTLAKE CORPORATION COM Stock 960413102 473 -5 -1.05 46 -23.33 0.0021
2022-04-28 2022-03-31 13F WESTLAKE CORPORATION COM Stock 960413102 478 119 33.15 60 71.43 0.0024
2022-01-20 2021-12-31 13F WESTLAKE CHEM CORP COM Stock 960413102 359 65 22.11 35 29.63 0.0013
2021-11-02 2021-09-30 13F/A-1 WESTLAKE CHEM CORP COM Stock 960413102 294 95 47.74 27 50.00 0.0011
2021-10-22 2021-09-30 13F WESTLAKE CHEM CORP COM Stock 960413102 199 0 18 0.0008
2021-08-06 2021-06-30 13F WESTLAKE CHEM CORP COM Stock 960413102 199 0 0.00 18 0.00 0.0008
2021-04-23 2021-03-31 13F WESTLAKE CHEM CORP COM Stock 960413102 199 0 0.00 18 12.50 0.0008
2021-02-02 2020-12-31 13F WESTLAKE CHEM CORP COM Stock 960413102 199 -71 -26.30 16 -5.88 0.0009
2020-10-27 2020-09-30 13F WESTLAKE CHEM CORP COM Stock 960413102 270 -12 -4.26 17 13.33 0.0011
2020-07-16 2020-06-30 13F WESTLAKE CHEM CORP COM Stock 960413102 282 154 120.31 15 275.00 0.0010
2020-04-27 2020-03-31 13F WESTLAKE CHEM CORP COM Stock 960413102 128 -191 -59.87 4 -81.82 0.0003
2020-01-30 2019-12-31 13F WESTLAKE CHEM CORP COM Stock 960413102 319 48 17.71 22 22.22 0.0017
2019-11-01 2019-09-30 13F WESTLAKE CHEM CORP COM Stock 960413102 271 -69 -20.29 18 -25.00 0.0015
2019-08-05 2019-06-30 13F WESTLAKE CHEM CORP COM Stock 960413102 340 219 180.99 24 200.00 0.0023
2019-05-01 2019-03-31 13F WESTLAKE CHEM CORP COM Stock 960413102 121 0 0.00 8 0.00 0.0009
2019-02-05 2018-12-31 13F WESTLAKE CHEM CORP COM Stock 960413102 121 69 132.69 8 100.00 0.0011
2018-11-01 2018-09-30 13F WESTLAKE CHEM CORP COM Stock 960413102 52 0 0.00 4 -20.00 0.0005
2018-07-30 2018-06-30 13F WESTLAKE CHEM CORP COM Stock 960413102 52 0 0.00 5 -16.67 0.0007
2018-05-08 2018-03-31 13F WESTLAKE CHEM CORP COM Stock 960413102 52 0 0.00 6 0.00 0.0009
2018-02-13 2017-12-31 13F WESTLAKE CHEM CORP COM Stock 960413102 52 0 0.00 6 20.00 0.0010
2017-11-15 2017-09-30 13F/A-1 WESTLAKE CHEM CORP COM Stock 960413102 52 0 0.00 5 25.00 0.0009
2017-08-07 2017-06-30 13F WESTLAKE CHEM CORP COM Stock 960413102 52 0 0.00 4 33.33 0.0008
2017-05-12 2017-03-31 13F/A-1 WESTLAKE CHEM CORP COM Stock 960413102 52 52 3 0.0006
2017-05-12 2017-03-31 13F WESTLAKE CHEM CORP COM Stock 960413102 52 3
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.