Westlake Corporation
US ˙ NYSE ˙ US9604131022

SecurityWLK / Westlake Corporation
InstitutionSelect Equity Group, L.P.
Latest Disclosed Ownership0 shares
Latest Disclosed Value $ 0
Select Equity Group, L.P. closes position in WLK / Westlake Corporation

On May 15, 2026 - Select Equity Group, L.P. filed a 13F-HR form disclosing ownership of 0 shares of Westlake Corporation (US:WLK) valued at $0 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 74,997 shares of Westlake Corporation. The current value of the position is $0 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)
2026-05-15 2026-03-31 13F WESTLAKE COM 960413102 0 -100.00 0
2026-02-17 2025-12-31 13F WESTLAKE COM 960413102 74,997 -1,645,769 -95.64 5,545 -96.28 0.0239
2016-05-17 2016-03-31 13F WESTLAKE CHEM COM 960413102 0 -100.00 0 -100.00
2016-02-16 2015-12-31 13F WESTLAKE CHEM COM 960413102 2,361,112 -27.83 128,256 -24.45
2015-11-16 2015-09-30 13F WESTLAKE CHEMICAL COM 960413102 3,271,379 -2.38 169,752 -26.15
2015-08-14 2015-06-30 13F WESTLAKE CHEMICAL COM 960413102 3,351,022 -5.88 229,847 -10.27
2015-05-15 2015-03-31 13F WESTLAKE CHEMICAL COM 960413102 3,560,486 32.30 256,141 55.79
2015-02-17 2014-12-31 13F WESTLAKE CHEMICAL COM 960413102 2,691,291 56.40 164,411 10.34
2014-11-14 2014-09-30 13F WESTLAKE CHEMICAL COM 960413102 1,720,766 149,001
2014-08-14 2014-06-30 13F/A-1 WESTLAKE CHEMICAL COM 960413102 1,454,725 121,848
2014-08-14 2014-06-30 13F WESTLAKE CHEMICAL COM 960413102 1,454,725 121,848
2014-05-15 2014-03-31 13F WESTLAKE CHEMICAL COM 960413102 1,695,186 112,187
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.