Insider at

04

Insider transactions

05
0 buys (P) 0 sells (S) Net: $0 last 12 months, based on the transactions shown below

Price change vs current quote, split-adjusted for corporate actions since the filing — not benchmarked, not annualized, not size-weighted

DateTickerCodeSharesPriceValue Owned afterΔ ownA/Dvs now
March 27, 2020 WLK P 160,000 $39.08 $6,252,800 1,395,000 Direct +12.96% Acquired 62.5% (price as of 2026-10-02)
March 27, 2020 WLK P 16,975 $37.58 $637,920 47,257,252 Indirect +0.04% Acquired 69.0% (price as of 2026-10-02)
March 27, 2020 WLK P 42,295 $38.49 $1,627,935 47,299,547 Indirect +0.09% Acquired 65.0% (price as of 2026-10-02)
March 27, 2020 WLK P 89,443 $39.49 $3,532,104 47,388,990 Indirect +0.19% Acquired 60.8% (price as of 2026-10-02)
March 27, 2020 WLK P 11,287 $40.31 $454,979 47,400,277 Indirect +0.02% Acquired 57.5% (price as of 2026-10-02)
March 26, 2020 WLK P 145,000 $41.00 $5,945,000 1,235,000 Direct +13.30% Acquired 54.9% (price as of 2026-10-02)
March 26, 2020 WLK P 42,199 $40.47 $1,707,794 47,137,476 Indirect +0.09% Acquired 56.9% (price as of 2026-10-02)
March 26, 2020 WLK P 94,001 $41.15 $3,868,141 47,231,477 Indirect +0.20% Acquired 54.3% (price as of 2026-10-02)
March 26, 2020 WLK P 8,800 $41.99 $369,512 47,240,277 Indirect +0.02% Acquired 51.2% (price as of 2026-10-02)
March 25, 2020 WLK P 130,000 $40.77 $5,300,100 1,090,000 Direct +13.54% Acquired 55.8% (price as of 2026-10-02)
March 25, 2020 WLK P 6,651 $37.98 $252,605 46,971,928 Indirect +0.01% Acquired 67.2% (price as of 2026-10-02)
March 25, 2020 WLK P 24,231 $38.87 $941,859 46,996,159 Indirect +0.05% Acquired 63.4% (price as of 2026-10-02)
March 25, 2020 WLK P 27,671 $39.83 $1,102,136 47,023,830 Indirect +0.06% Acquired 59.4% (price as of 2026-10-02)
March 25, 2020 WLK P 14,025 $40.96 $574,464 47,037,855 Indirect +0.03% Acquired 55.0% (price as of 2026-10-02)
March 25, 2020 WLK P 33,358 $42.02 $1,401,703 47,071,213 Indirect +0.07% Acquired 51.1% (price as of 2026-10-02)
March 25, 2020 WLK P 24,064 $42.69 $1,027,292 47,095,277 Indirect +0.05% Acquired 48.7% (price as of 2026-10-02)
March 24, 2020 WLK P 145,000 $36.53 $5,296,850 960,000 Direct +17.79% Acquired 73.8% (price as of 2026-10-02)
March 24, 2020 WLK P 4,738 $34.94 $165,546 46,825,015 Indirect +0.01% Acquired 81.7% (price as of 2026-10-02)
March 24, 2020 WLK P 57,419 $36.00 $2,067,084 46,882,434 Indirect +0.12% Acquired 76.4% (price as of 2026-10-02)
March 24, 2020 WLK P 67,812 $36.86 $2,499,550 46,950,246 Indirect +0.14% Acquired 72.3% (price as of 2026-10-02)
March 24, 2020 WLK P 15,031 $37.60 $565,166 46,965,277 Indirect +0.03% Acquired 68.9% (price as of 2026-10-02)
March 19, 2020 WLK P 165,000 $37.66 $6,213,900 815,000 Direct +25.38% Acquired 68.6% (price as of 2026-10-02)
March 19, 2020 WLK P 3,002 $35.23 $105,760 46,658,279 Indirect +0.01% Acquired 80.2% (price as of 2026-10-02)
March 19, 2020 WLK P 22,497 $36.20 $814,391 46,680,776 Indirect +0.05% Acquired 75.4% (price as of 2026-10-02)
March 19, 2020 WLK P 54,388 $38.22 $2,078,709 46,798,500 Indirect +0.12% Acquired 66.1% (price as of 2026-10-02)
March 19, 2020 WLK P 21,777 $39.09 $851,263 46,820,277 Indirect +0.05% Acquired 62.4% (price as of 2026-10-02)
March 18, 2020 WLK P 165,000 $31.41 $5,182,650 650,000 Direct +34.02% Acquired 102.2% (price as of 2026-10-02)
March 18, 2020 WLK P 63,336 $37.32 $2,363,700 46,744,112 Indirect +0.14% Acquired 70.2% (price as of 2026-10-02)
March 18, 2020 WLK P 25,970 $30.58 $794,163 46,516,247 Indirect +0.06% Acquired 107.7% (price as of 2026-10-02)
March 18, 2020 WLK P 99,940 $31.31 $3,129,121 46,616,187 Indirect +0.21% Acquired 102.8% (price as of 2026-10-02)
March 18, 2020 WLK P 36,790 $32.13 $1,182,063 46,652,977 Indirect +0.08% Acquired 97.6% (price as of 2026-10-02)
March 18, 2020 WLK P 2,300 $33.03 $75,969 46,655,277 Indirect 0.00% Acquired 92.2% (price as of 2026-10-02)
March 17, 2020 WLK P 165,000 $33.25 $5,486,250 485,000 Direct +51.56% Acquired 91.0% (price as of 2026-10-02)
March 17, 2020 WLK P 9,160 $30.21 $276,724 46,334,437 Indirect +0.02% Acquired 110.2% (price as of 2026-10-02)
March 17, 2020 WLK P 2,840 $31.63 $89,829 46,337,277 Indirect +0.01% Acquired 100.8% (price as of 2026-10-02)
March 17, 2020 WLK P 41,076 $32.51 $1,335,381 46,378,353 Indirect +0.09% Acquired 95.3% (price as of 2026-10-02)
March 17, 2020 WLK P 69,003 $33.40 $2,304,700 46,447,356 Indirect +0.15% Acquired 90.1% (price as of 2026-10-02)
March 17, 2020 WLK P 42,821 $34.46 $1,475,612 46,490,177 Indirect +0.09% Acquired 84.3% (price as of 2026-10-02)
March 17, 2020 WLK P 100 $35.06 $3,506 46,490,277 Indirect 0.00% Acquired 81.1% (price as of 2026-10-02)
March 16, 2020 WLK P 160,000 $31.42 $5,027,200 320,000 Direct +100.00% Acquired 102.1% (price as of 2026-10-02)
March 16, 2020 WLK P 90,472 $30.97 $2,801,918 46,255,749 Indirect +0.20% Acquired 105.0% (price as of 2026-10-02)
March 16, 2020 WLK P 57,203 $31.88 $1,823,632 46,312,952 Indirect +0.12% Acquired 99.2% (price as of 2026-10-02)
March 16, 2020 WLK P 12,325 $32.63 $402,165 46,325,277 Indirect +0.03% Acquired 94.6% (price as of 2026-10-02)
March 13, 2020 WLK P 160,000 $32.94 $5,270,400 160,000 Direct · Acquired 92.8% (price as of 2026-10-02)
March 13, 2020 WLK P 113,737 $32.71 $3,720,337 46,119,014 Indirect +0.25% Acquired 94.1% (price as of 2026-10-02)
March 13, 2020 WLK P 46,263 $33.52 $1,550,736 46,165,277 Indirect +0.10% Acquired 89.4% (price as of 2026-10-02)
March 29, 2019 WLKP P 1,401,869 $21.40 $29,999,997 1,401,869 Direct · Acquired -0.6% (price as of 2026-10-02)
May 2, 2006 WLK S 5,500,000 $30.16 $165,880,000 46,005,277 Indirect -10.68% Disposed 321.1% (price as of 2026-10-02)

P = Open-market purchase · S = Sale · A = Grant/award · M = Option exercise · G = Gift · F = Tax withholding

Insider transactions are not a recommendation; sales are often driven by liquidity or tax reasons.

Initial ownership (Form 3) 1 holding

07

Securities held when first becoming an insider, per SEC Form 3.

DateTickerSecuritySharesOwnership
Aug. 9, 2004 WLK common stock 51,505,277 Indirect