Key facts
- William F. Masterson III has 1 issuer position tracked on this page.
- Estimated disclosed ownership value: $470,481.
- Recent insider filing activity is available below.
Insider Trading & Ownership of William F. Masterson III
- Location
- Boston, MA
- Summary
- The estimated net worth of William F. Masterson III is at least $470,481 dollars as of 17 Mar 2026. William F. Masterson III is the Senior Vice President of CABOT CORP and owns shares of CABOT CORP (CBT) stock worth about $470.5K.
- Signature
- By: Jennifer Lombardi, pursuant to a power of attorney from William F. Masterson, III
- All Insider Reports
- All Insider Reports
Follow Filing Activity
Follow William F. Masterson III and return when a new Insider Trading filing changes the record on this page.
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Change
- Largest disclosed position: CABOT CORP ($470,481).
- Past-year value change for that position: .
Research use
- This page translates Forms 3/4/5 into a quick ownership context before you inspect each transaction row.
- You can cross-check role, issuer, and filing chronology directly against the SEC source.
Evidence
Filed on Form 4
See Original Filing
Insider ownership context is sourced from SEC Forms 3, 4, and 5.
Ownership of William F. Masterson III
CBT
Forms 3/4/5
CABOT CORP
- Relationship
- Senior Vice President
- Holdings value
- $470,481
- Past year net change
- Change %
- Report period
- 13 Mar 2026
Insider Transactions Reported by William F. Masterson III:
| Sym | Company | Class | Transaction | % | Value $ | * Price $ | Shares | Shares After | Date | Ownership |
|---|
* An asterisk sign (*) next to the price indicates that the price is likely invalid.