MarketPeel
Insider Trading Intelligence
WK

William C. Kirby

CBT
DIRECTOR · CABOT CORP · CIK 0001413483
FILING MIX · LIFETIME100%/0%
BUYS
9
SELLS
0
TOTAL VALUE
$3.30M
COMPANIES
2
ACTIVE SINCE
Jan 2020
HOLDINGS NOW
30,574
AVG SELL PX
TRADE KIND
SHOWING 9 / 9
Trades · vs SPY
Loading price series…
Performance · forward returns vs SPY
2 backtested trades · 8 horizons · 3 pendingHow are these numbers computed? →
Forward-return performance of every backtestable P/S trade by William C. Kirby, measured at 8 horizons from 7 days to 2 years. Deduped per economic event so co-filings count once. Excess return = trade return minus SPY return over the same window.
HORIZONTRADESWIN RATEINSIDER RETURNSPY RETURNMEAN EXCESSMEDIAN EXCESST-STAT
7d2+50.00%-0.94%+0.35%-1.29%-1.29%
14d2+50.00%+3.24%-0.39%+3.63%+3.63%
30d2+100.00%+7.86%-2.21%+10.07%+10.07%
60d2+100.00%+32.53%+5.95%+26.58%+26.58%
90d2+100.00%+45.04%+10.77%+22.48%+22.48%
180d2(1 pending)+100.00%+47.41%+18.94%+28.48%+28.48%
1y2(1 pending)+100.00%+73.88%+32.80%+41.09%+41.09%
2y2(1 pending)+100.00%+7.48%+14.77%-7.29%-7.29%
How to read this: Insider Returnis the average raw return of the filer's trades over the horizon. SPY Return is what SPY did over those same windows — reference only, not a comparison. The headline alpha number is Mean Excess = Insider − SPY; green means the filer beat SPY, red means they trailed it. Win rate is the share of individual trades where the filer beat SPY. T-statvalues above 2 mean the alpha is unlikely to be chance given the sample size. "Pending" counts trades where the horizon hasn't elapsed yet; their stats are not included in the row average.
Holdings over time
CBT · 27,688 shares · as of Jan 8, 2026
06,92213,84420,76627,688202120222023202420252026SHARES HELD
Trading cadence · quarterly flow
BUY SELL
2020
2020
2020
2020
2021
2021
2021
2021
2022
2022
2022
2022
2023
2023
2023
2023
2024
2024
2024
2024
2025
2025
2025
2025
2026
FLOW · 9 buys / 0 sellsCOVERAGE · 25 quarters
Form 4 filings · all activity
COMPANYTYPESHARESPRICEVALUEHELD AFTERTRADE DATEFILEDDETAILS
TWN
TAIWAN FUND INC
PURCHASE
50,686.9$64.90$3.29M2,886Feb 26, 2026Feb 27, 2026View →
CBT
CABOT CORP
PURCHASEGRANT
Stock grant
48627,688Jan 8, 2026Jan 12, 2026View →
CBT
CABOT CORP
PURCHASEGRANT
Stock grant
1,78827,202Jan 10, 2025Jan 14, 2025View →
CBT
CABOT CORP
PURCHASEGRANT
Stock grant
2,03525,414Jan 11, 2024Jan 12, 2024View →
CBT
CABOT CORP
PURCHASEGRANT
Stock grant
1,85423,379Jan 12, 2023Jan 13, 2023View →
CBT
CABOT CORP
PURCHASEGRANT
Stock grant
2,25421,525Jan 13, 2022Jan 14, 2022View →
CBT
CABOT CORP
PURCHASEGRANT
Stock grant
2,48919,271Jan 7, 2021Jan 11, 2021View →
TWN
TAIWAN FUND INC
PURCHASE
415$24.45$10.1K1,745Nov 10, 2020Nov 11, 2020View →
CBT
CABOT CORP
PURCHASEGRANT
Stock grant
2,63516,782Jan 9, 2020Jan 13, 2020View →
Other insiders · CBT
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About this filer
CIK 0001413483
ROLE
Director
PRIMARY
CBT
COMPANIES
2
ACTIVE SINCE
Jan 2020
MARKETPEEL · /INSIDER/0001413483DATA · SEC EDGAR · FORM 4 · CONSOLIDATED TAPE
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