Westlake Corporation
US ˙ NYSE ˙ US9604131022

SecurityWLK / Westlake Corporation
InstitutionMercer Global Advisors Inc /adv
Latest Disclosed Ownership5,717 shares
Latest Disclosed Value $ 667,802
Mercer Global Advisors Inc /adv reports 45.73% increase in ownership of WLK / Westlake Corporation

On May 15, 2026 - Mercer Global Advisors Inc /adv filed a 13F-HR form disclosing ownership of 5,717 shares of Westlake Corporation (US:WLK) valued at $667,860 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 3,923 shares of Westlake Corporation. This represents a change in shares of 45.73% during the quarter. The current value of the position is $483,887 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)
2026-05-15 2026-03-31 13F WESTLAKE COM 960413102 5,717 1,794 45.73 668 130.00 0.0010
2026-02-17 2025-12-31 13F WESTLAKE COM 960413102 3,923 -318 -7.50 290 -11.04 0.0004
2025-11-14 2025-09-30 13F WESTLAKE COM 960413102 4,241 -1,029 -19.53 327 -18.50 0.0005
2025-08-14 2025-06-30 13F WESTLAKE COM 960413102 5,270 -3,765 -41.67 400 -55.70 0.0008
2025-05-15 2025-03-31 13F WESTLAKE COM 960413102 9,035 -2,625 -22.51 904 -32.41 0.0021
2025-02-14 2024-12-31 13F WESTLAKE COM 960413102 11,660 -3,834 -24.75 1,337 -42.16 0.0033
2024-11-14 2024-09-30 13F WESTLAKE COM 960413102 15,494 -3,574 -18.74 2,311 -16.33 0.0054
2024-08-12 2024-06-30 13F WESTLAKE COM 960413102 19,068 -6,614 -25.75 2,761 91,933.33 0.0075
2024-05-15 2024-03-31 13F WESTLAKE COM 960413102 25,682 786 3.16 4 0.00 0.0112
2024-02-15 2023-12-31 13F WESTLAKE CHEM COM 960413102 24,896 910 3.79 3 50.00 0.0105
2023-11-15 2023-09-30 13F/A-1 WESTLAKE COM 960413102 23,986 -2,332 -8.86 3 -33.33 0.0114
2023-11-14 2023-09-30 13F WESTLAKE COM 960413102 23,986 -2,332 3 0.0114
2023-08-14 2023-06-30 13F WESTLAKE COM 960413102 26,318 -1,813 -6.44 3 0.00 0.0125
2023-05-16 2023-03-31 13F WESTLAKE COM 960413102 28,131 -795 -2.75 3 50.00 0.0148
2023-02-09 2022-12-31 13F WESTLAKE CHEM COM 960413102 28,926 3,809 15.17 3 -99.91 0.0149
2022-11-15 2022-09-30 13F WESTLAKE CHEM COM 960413102 25,117 6,405 34.23 2,182 18.97 0.0129
2022-08-10 2022-06-30 13F WESTLAKE CHEM COM 960413102 18,712 8,233 78.57 1,834 41.84 0.0112
2022-05-10 2022-03-31 13F WESTLAKE CHEM COM 960413102 10,479 852 8.85 1,293 38.29 0.0076
2022-02-04 2021-12-31 13F WESTLAKE CHEM COM 960413102 9,627 814 9.24 935 16.44 0.0058
2021-11-10 2021-09-30 13F WESTLAKE CHEM COM 960413102 8,813 -5,969 -40.38 803 -39.71 0.0056
2021-08-10 2021-06-30 13F WESTLAKE CHEM COM 960413102 14,782 263 1.81 1,332 3.34 0.0102
2021-08-10 2021-03-31 13F/A-1 WESTLAKE CHEM COM 960413102 14,519 6,288 76.39 1,289 91.82 0.0117
2021-05-11 2021-03-31 13F WESTLAKE CHEM COM 960413102 14,519 6,288 1,289 0.0123
2021-02-12 2020-12-31 13F WESTLAKE CHEM COM 960413102 8,231 -75 -0.90 672 28.00 0.0084
2020-12-10 2020-09-30 13F WESTLAKE CHEM COM 960413102 8,306 56 0.68 525 18.51 0.0079
2020-08-10 2020-06-30 13F WESTLAKE CHEM COM 960413102 8,250 -1,253 -13.19 443 22.04 0.0080
2020-05-18 2020-03-31 13F WESTLAKE CHEM COM 960413102 9,503 2,982 45.73 363 -20.57 0.0080
2020-02-13 2019-12-31 13F WESTLAKE CHEM CORP COM COM 960413102 6,521 213 3.38 457 10.65 0.0091
2019-11-12 2019-09-30 13F WESTLAKE CHEM CORP COM COM 960413102 6,308 -257 -3.91 413 -9.43 0.0097
2019-08-14 2019-06-30 13F WESTLAKE CHEM CORP COM COM 960413102 6,565 201 3.16 456 5.56 0.0121
2019-04-23 2019-03-31 13F/A-1 WESTLAKE CHEM CORP COM COM 960413102 6,364 6,364 432 0.0155
2019-04-12 2019-03-31 13F WESTLAKE CHEM CORP COM COM 960413102 7,973 528 0.0281
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.