DAVIDSON CHARLES E (CIK 1001391) reported 6 SEC Form 4 insider transactions across 2 companies over the past 18 months (most recent 2026-08-20). Recent activity: Buy NEPH (812 shares), Buy TUSK (1.1M shares), Buy TUSK (2.4M shares), Buy TUSK (6.4M shares), Buy TUSK (4.1M shares). Source: SEC Form 4.
| Date | Company | Role | Type | Shares | Value |
|---|---|---|---|---|---|
| 2026-08-20 | NEPHROS INC (NEPH) | 10% Owner | Buy | 812 | $2,923 |
| 2026-06-22 | MAMMOTH ENERGY SERVICES, INC. (TUSK) | Chief Business Officer | Buy | 1.1M | $0 |
| 2026-06-22 | MAMMOTH ENERGY SERVICES, INC. (TUSK) | 10% Owner | Buy | 2.4M | $0 |
| 2026-06-22 | MAMMOTH ENERGY SERVICES, INC. (TUSK) | Chief Business Officer | Buy | 6.4M | $0 |
| 2026-06-22 | MAMMOTH ENERGY SERVICES, INC. (TUSK) | 10% Owner | Buy | 4.1M | $0 |
| 2026-06-22 | MAMMOTH ENERGY SERVICES, INC. (TUSK) | Chief Business Officer | Buy | 4.0M | $10.5M |
Source: SEC Form 4 filings · as of 2026-08-20