Summary
Updated Aug 30, 2026
William D. Lambert is EVP and CFO of Matador Resources Co (MTDR). 1 SEC Form 4 filing on record, dated 12 September 2025. Most recent open-market trade: bought $7K of MTDR on 12 September 2025. Lifetime open-market purchases: $7K.
Recent Transactions
1Every recent SEC Form 4 transaction William D. Lambert has reported, most recent first.
Trading Pattern
InsiderAlpha's records for William D. Lambert go back to 2025: 1 primary Form 4 filing, an average of 0.5 per year. The typical open-market purchase is $7K (1 buy totaling $7K). The largest single buy on record is $7K of MTDR in 2025. No transaction on record carries a Rule 10b5-1 flag - the filings look discretionary rather than pre-scheduled, which makes their timing more informative as a signal.
Other Insiders Active in the Same Stocks
Insiders who reported open-market trades in the last 12 months at the companies William D. Lambert files at. Multiple unrelated insiders buying the same stock within a short window, cluster buying, has historically been one of the strongest Form 4 signals.
- Joseph Wm Foran - $2.26M of MTDR open-market activity in the last 12 months
- Shelley F. Appel - $287K of MTDR open-market activity in the last 12 months
- Christopher P. Calvert - $226K of MTDR open-market activity in the last 12 months
- Susan M. Ward - $195K of MTDR open-market activity in the last 12 months
- Glenn W. Stetson - $106K of MTDR open-market activity in the last 12 months
- Robert T. Macalik - $98K of MTDR open-market activity in the last 12 months
More Notable Insiders
Other corporate insiders with significant SEC Form 4 track records on InsiderAlpha:
Frequently Asked Questions
Who is William D. Lambert?
William D. Lambert is a corporate insider, tracked as EVP and CFO of Matador Resources Co (MTDR). InsiderAlpha holds 1 primary Form 4 filing for them, the earliest from 2025, updated as new SEC EDGAR filings are processed.
When did William D. Lambert last file a Form 4?
The only primary Form 4 on record is dated 12 September 2025.
Has William D. Lambert been buying or selling stock?
Recorded transactions: 1 open-market purchase ($7K) and 0 open-market sales across all tracked filings.
Where can I see all of William D. Lambert's SEC filings?
All Form 4 filings, transaction values, and 10b5-1 plan flags are listed on this page and updated in real time as new SEC EDGAR filings are processed.
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