Updated Jul 16, 2026 · Last SEC filing 2026-06-16
WESTLAKE CORP (WLK) has filed 2 SEC Form 4 insider transactions in the last 90 days, with the most recent on 2026-06-16. 5 Form 8-K material event filings were reported by WLK in the last 90 days. InsiderAlpha tracks every WLK SEC filing — Form 4, Form 144, and 8-K — in real time, including Rule 10b5-1 plan detection.
| SIC classification | Industrial Organic Chemicals (SIC 2860) |
|---|---|
| SEC CIK | 0001262823 |
| Form 4 filings (90d) | 2 |
|---|---|
| Form 8-K filings (90d) | 5 |
| Latest Form 4 filing | 2026-06-16 |
| Date | Insider | Role | Transaction | Shares | Price | Value | Filing |
|---|---|---|---|---|---|---|---|
| Bender Mark Steven | EVP & CFO | F — Tax withholding / forfeiture | 5.3K | $97.34 | $514K | SEC | |
| Bender Mark Steven | EVP & CFO | M — Option exercise | 13.2K | $0.00 | — | SEC | |
| Bender Mark Steven | EVP & CFO | S — Open-market sale | 16.4K | $112.53 | $1.85M | SEC | |
| Buesinger Robert F. | EVP, PEM Segment Head | S — Open-market sale | 4.0K | $115.25 | $461K | SEC | |
| Bender Mark Steven | EVP & CFO | S — Open-market sale | 17.0K | $100.91 | $1.71M | SEC | |
| Bender Mark Steven | EVP & CFO | M — Option exercise | 6.2K | $65.81 | $408K | SEC | |
| Bender Mark Steven | EVP & CFO | M — Option exercise | 6.5K | $86.54 | $562K | SEC | |
| Bender Mark Steven | EVP & CFO | D — Derivative transaction | 12.7K | $98.20 | $1.25M | SEC | |
| Bender Mark Steven | EVP & CFO | S — Open-market sale | 421 | $101.52 | $43K | SEC | |
| Ederington L. Benjamin | EVP, Legal & External Affairs | F — Tax withholding / forfeiture | 357 | $94.10 | $34K | SEC | |
| Holy Jeffrey Adam | VP and CAO | F — Tax withholding / forfeiture | 81 | $94.10 | $8K | SEC | |
| Chao James | Senior Chairman | F — Tax withholding / forfeiture | 1.6K | $94.10 | $148K | SEC | |
| Buesinger Robert F. | EVP, PEM Segment Head | F — Tax withholding / forfeiture | 326 | $94.10 | $31K | SEC | |
| Szwejbka Scott Thomas | SVP, HIP Segment Head | F — Tax withholding / forfeiture | 91 | $94.10 | $9K | SEC | |
| Chao Albert | Executive Chairman | F — Tax withholding / forfeiture | 2.5K | $94.10 | $235K | SEC |
All transactions sourced from SEC EDGAR Form 4 filings for WESTLAKE CORP (WLK). Updated in real time as new filings are submitted to the SEC.
| Insider | Form 4 filings | Total transaction value |
|---|---|---|
| Bender Mark Steven | 3 | $514K |
| Baksht Jonathan | 1 | — |
SEC Form 4 transactions are reported with a one-letter code indicating the type of transaction. Common codes you'll see in WLK insider filings:
| P | Open-market purchase by the insider |
|---|---|
| S | Open-market sale by the insider |
| A | Grant, award, or other acquisition from the issuer |
| M | Exercise or conversion of derivative security (e.g. options) |
| F | Payment of exercise price or tax liability via share withholding |
| G | Bona-fide gift of securities |
| D | Disposition to the issuer (e.g. share buyback participation) |
| J | Other acquisition or disposition |
| X | Exercise of in-the-money or at-the-money derivative security |
| C | Conversion of derivative security |
| V | Transaction voluntarily reported earlier than required |
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