Westlake Corporation
US ˙ NYSE ˙ US9604131022

SecurityWLK / Westlake Corporation
InstitutionWalleye Capital LLC
Latest Disclosed Ownership59,814 shares
Latest Disclosed Value $ 6,987,471
Walleye Capital LLC ownership in WLK / Westlake Corporation

On May 13, 2026 - Walleye Capital LLC filed a 13F-HR/A form disclosing ownership of 59,814 shares of Westlake Corporation (US:WLK) valued at $6,987,471 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 47,657 shares of Westlake Corporation. This represents a change in shares of 25.51% during the quarter. The current value of the position is $5,062,657 USD.

Walleye Capital LLC has a history of taking positions in derivatives of the underlying security (WLK) in the form of stock options. The firm currently holds call options representing 16,800 of underlying shares valued at $1,962,576 USD and put options representing 2,400 of underlying shares valued at $280,368 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

WLK / Westlake Corporation Historical Put/Call Ratio
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)
2026-05-13 2026-03-31 13F/A-1 WESTLAKE COM 960413102 59,814 12,157 25.51 6,987 98.33 0.0291
2026-05-08 2026-03-31 13F WESTLAKE COM 960413102 59,814 12,157 6,987 0.0290
2026-02-13 2025-12-31 13F WESTLAKE COM 960413102 47,657 -100,660 -67.87 3,524 -69.17 0.0108
2025-11-14 2025-09-30 13F WESTLAKE COM 960413102 148,317 36,119 32.19 11,429 34.16 0.0429
2025-08-13 2025-06-30 13F WESTLAKE COM 960413102 112,198 77,821 226.38 8,519 147.79 0.0331
2025-05-14 2025-03-31 13F WESTLAKE COM 960413102 34,377 27,672 412.71 3,439 347.66 0.0155
2025-02-13 2024-12-31 13F WESTLAKE COM 960413102 6,705 -50,790 -88.34 769 -91.11 0.0019
2024-11-14 2024-09-30 13F WESTLAKE COM 960413102 57,495 35,683 163.59 8,641 173.59 0.0180
2024-08-14 2024-06-30 13F WESTLAKE COM 960413102 21,812 12,005 122.41 3,159 110.81 0.0056
2024-05-15 2024-03-31 13F WESTLAKE COM 960413102 9,807 9,807 1,499 0.0027
2022-11-14 2022-09-30 13F WESTLAKE COM 960413102 0 -3,857 -100.00 0 -100.00
2022-08-19 2022-06-30 13F/A-1 WESTLAKE COM 960413102 3,857 -99 -2.50 378 -22.54 0.0104
2022-08-08 2022-06-30 13F WESTLAKE COM 960413102 3,857 -99 378 0.0104
2022-05-27 2022-03-31 13F/A-01 WESTLAKE COM 960413102 3,956 -2,355 -37.32 488 -20.39 0.0130
2022-05-16 2022-03-31 13F WESTLAKE COM 960413102 3,956 -2,355 488 0.0099
2022-05-27 2021-12-31 13F/A-01 WESTLAKE CHEM COM 960413102 6,311 -47,782 -88.33 613 -87.57 0.0190
2022-03-03 2021-12-31 13F WESTLAKE CHEM COM 960413102 6,311 -47,782 613 0.0153
2021-11-15 2021-09-30 13F WESTLAKE CHEM COM 960413102 54,093 42,991 387.24 4,930 393.00 0.1397
2021-08-16 2021-06-30 13F WESTLAKE CHEM COM 960413102 11,102 -2,411 -17.84 1,000 -16.67 0.0341
2021-05-17 2021-03-31 13F WESTLAKE CHEM COM 960413102 13,513 -10,434 -43.57 1,200 -38.59 0.0695
2021-02-16 2020-12-31 13F WESTLAKE CHEM COM 960413102 23,947 23,947 1,954 0.1305
2019-11-14 2019-09-30 13F WESTLAKE CHEM COM 960413102 0 -1,430 -100.00 0 -100.00
2019-08-14 2019-06-30 13F WESTLAKE CHEM COM 960413102 1,430 1,430 99 0.0109
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-13 2026-03-31 13F/A WESTLAKE COM Call 16,800 -50.59 1,963 -21.93 n/a n/a n/a
2026-05-08 2026-03-31 13F WESTLAKE COM Call 16,800 1,963 n/a n/a n/a
2026-02-13 2025-12-31 13F WESTLAKE COM Call 34,000 106.06 2,514 97.72 n/a n/a n/a
2025-11-14 2025-09-30 13F WESTLAKE COM Call 16,500 -53.65 1,271 -52.98 n/a n/a n/a
2025-08-13 2025-06-30 13F WESTLAKE COM Call 35,600 2,703 n/a n/a n/a
2025-05-14 2025-03-31 13F WESTLAKE COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-02-13 2024-12-31 13F WESTLAKE COM Call 500 -50.00 57 -62.00 n/a n/a n/a
2024-11-14 2024-09-30 13F WESTLAKE COM Call 1,000 -28.57 150 -25.74 n/a n/a n/a
2024-08-14 2024-06-30 13F WESTLAKE COM Call 1,400 1,300.00 203 1,246.67 n/a n/a n/a
2024-05-15 2024-03-31 13F WESTLAKE COM Call 100 15 n/a n/a n/a
2023-11-21 2023-09-30 13F/A WESTLAKE COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2023-11-14 2023-09-30 13F WESTLAKE COM Call 0 0 n/a n/a n/a
2023-08-14 2023-06-30 13F WESTLAKE COM Call 300 -85.00 36 -84.85 n/a n/a n/a
2023-05-15 2023-03-31 13F WESTLAKE COM Call 2,000 232 n/a n/a n/a
2019-11-14 2019-09-30 13F WESTLAKE CHEM COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2019-08-14 2019-06-30 13F WESTLAKE CHEM COM Call 4,400 306 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-13 2026-03-31 13F/A WESTLAKE COM Put 2,400 -64.71 280 -44.22 n/a n/a n/a
2026-05-08 2026-03-31 13F WESTLAKE COM Put 2,400 280 n/a n/a n/a
2026-02-13 2025-12-31 13F WESTLAKE COM Put 6,800 -75.63 503 -76.64 n/a n/a n/a
2025-11-14 2025-09-30 13F WESTLAKE COM Put 27,900 -37.58 2,150 -36.68 n/a n/a n/a
2025-08-13 2025-06-30 13F WESTLAKE COM Put 44,700 3,394 n/a n/a n/a
2025-02-13 2024-12-31 13F WESTLAKE COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2024-11-14 2024-09-30 13F WESTLAKE COM Put 2,700 -10.00 406 -6.68 n/a n/a n/a
2024-08-14 2024-06-30 13F WESTLAKE COM Put 3,000 233.33 434 216.79 n/a n/a n/a
2024-05-15 2024-03-31 13F WESTLAKE COM Put 900 138 n/a n/a n/a
2023-11-21 2023-09-30 13F/A WESTLAKE COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2023-11-14 2023-09-30 13F WESTLAKE COM Put 0 0 n/a n/a n/a
2023-08-14 2023-06-30 13F WESTLAKE COM Put 2,600 -57.38 311 -56.15 n/a n/a n/a
2023-05-15 2023-03-31 13F WESTLAKE COM Put 6,100 707 n/a n/a n/a
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.