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Westlake stock timeline
A year of the price with every insider trade, planned sale, earnings report and material 8-K marked
252 sessions+1.2% to $63.49
Westlake (WLK) stock rose 1% over the last 252 sessions, to $63.49. On the way it reported 4 quarters, its insiders filed 4 open-market trades and 1 Form 144 notice of planned sales, and the company filed 7 material 8-Ks. Each is marked on the price and listed with what the stock did next.
Each mark, and what followed
| Date | Kind | What | Next session | 5 sessions | 21 sessions |
|---|---|---|---|---|---|
| Nov 4, 2026 | Earnings | Earnings: missed the EPS estimate by -10.4% | −0.8% (−2.5% vs SPY) | — | — |
| Sep 29, 2026 | 8-K | Exit or disposal costs | −5.3% (−5.1% vs SPY) | −3.4% (−4.6% vs SPY) | −1.0% (−1.5% vs SPY) |
| Aug 31, 2026 | 8-K | Directors and officers: departures, appointments, pay | −1.1% (−0.4% vs SPY) | −0.4% (−0.3% vs SPY) | −18.6% (−18.3% vs SPY) |
| Aug 11, 2026 | Form 144 | Form 144: Albert Y Chao plans to sell $3.1M | +2.2% (+2.5% vs SPY) | −1.1% (−1.1% vs SPY) | −9.0% (−7.6% vs SPY) |
| Aug 11, 2026 | Insider sale | Chao Albert sold $3.1M | +2.2% (+2.5% vs SPY) | −1.1% (−1.1% vs SPY) | −9.0% (−7.6% vs SPY) |
| Aug 4, 2026 | Earnings | Earnings: beat the EPS estimate by 6.6% | +14.3% (+12.5% vs SPY) | +12.4% (+10.3% vs SPY) | +6.7% (+6.2% vs SPY) |
| May 5, 2026 | Earnings | Earnings: missed the EPS estimate by -225.0% | −9.2% (−10.0% vs SPY) | −16.3% (−19.2% vs SPY) | −27.9% (−32.8% vs SPY) |
| Apr 20, 2026 | 8-K | Directors and officers: departures, appointments, pay | +1.5% (+2.2% vs SPY) | −2.4% (−3.3% vs SPY) | −25.0% (−28.5% vs SPY) |
| Apr 6, 2026 | 8-K | Material definitive agreement | +0.1% (−0.4% vs SPY) | −0.9% (−4.4% vs SPY) | −3.9% (−12.9% vs SPY) |
| Apr 2, 2026 | 8-K | Directors and officers: departures, appointments, pay | +2.4% (+2.3% vs SPY) | +0.5% (−3.2% vs SPY) | −1.4% (−10.9% vs SPY) |
| Mar 27, 2026 | Insider sale | Buesinger Robert F. sold $461K | −0.2% (+1.6% vs SPY) | +5.1% (+3.4% vs SPY) | −2.0% (−12.4% vs SPY) |
| Mar 27, 2026 | Insider sale | Bender Mark Steven sold $1.8M | −0.2% (+1.6% vs SPY) | +5.1% (+3.4% vs SPY) | −2.0% (−12.4% vs SPY) |
| Feb 27, 2026 | Insider sale | Bender Mark Steven sold $1.8M | +4.9% (+5.4% vs SPY) | +5.5% (+6.7% vs SPY) | +12.7% (+20.7% vs SPY) |
| Feb 24, 2026 | Earnings | Earnings: beat the EPS estimate by 83.0% | +11.3% (+10.6% vs SPY) | +13.8% (+13.2% vs SPY) | +20.9% (+25.1% vs SPY) |
| Feb 23, 2026 | 8-K | Directors and officers: departures, appointments, pay | +11.3% (+10.6% vs SPY) | +13.8% (+13.2% vs SPY) | +20.9% (+25.1% vs SPY) |
| Dec 15, 2025 | 8-K | Exit or disposal costs | −1.0% (−0.9% vs SPY) | −2.6% (−2.7% vs SPY) | +18.9% (+17.3% vs SPY) |
Insiders’ record here
In the year on the chart, Westlake's insiders reported 0 open-market buys ($0) and 4 sales ($7.2M). Of the 3 old enough to score, 3 were followed by the stock doing what the trade implied over the next 63 sessions (beating SPY after a buy, lagging it after a sale); the median excess return after a buy was — and after a sale −50.9%.
Across the whole universe (19,782 scored trades), insider buys beat the market 46% of the time and sales were followed by a lagging stock 61% of the time; buys of $1M or more 39%. Every pattern →
What this kind of 8-K usually did
| Item | 8-Ks | Next session, median | Up next session | 21 sessions, median | Typical size |
|---|---|---|---|---|---|
| 2.05 Exit or disposal costs | 954 | −0.2% | 47% | +0.5% | ±2.4% |
| 5.02 Directors and officers: departures, appointments, pay | 39,174 | −0.1% | 48% | +0.7% | ±1.4% |
| 1.01 Material definitive agreement | 23,525 | 0.0% | 51% | +1.0% | ±1.4% |
| 1.02 Termination of a material agreement | 2,368 | 0.0% | 51% | +1.1% | ±1.5% |
| 2.03 New debt or off-balance-sheet obligation | 13,268 | 0.0% | 50% | +1.2% | ±1.3% |
Across every company in the move-odds universe, measured from the close before the filing. Every 8-K item ranked →
Report card: every quarter against the estimate → Westlake: every quarter → Live insider trades →
Prices are daily closes; filings and trades are as filed with the SEC (Form 4 within two business days of the trade, 8-K within four of the event). Moves after a mark are the stock's close-to-close change and the same for SPY; they describe the record, not what the next one will do. Not investment advice.