Leonard Osser - SEC Form 4 Insider Trading Activity
Summary
Updated Aug 4, 2026
Leonard Osser is a corporate insider tracked by InsiderAlpha. No SEC Form 4 filings recorded in the last 90 days. Lifetime open-market sales: $100K.
Profile
Leonard Osser is a beneficial owner of more than 10% of Nexalin Technology, Inc. (NXL), as disclosed in SEC ownership filings. SEC records also connect Osser to MILESTONE SCIENTIFIC INC. (MLSS). Osser has reported 2 insider filings with the SEC since 2024. The most recent filing was in September 2025.
| Role | 10% Owner |
|---|---|
| Notability | 36/100 |
Board memberships
- Nexalin Technology, Inc.
- MILESTONE SCIENTIFIC INC.
Reported roles
- 10% Owner
- Director
Trading Pattern
InsiderAlpha's records for Leonard Osser go back to 2024: 2 primary Form 4 filings, an average of 0.7 per year. 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.
Career & Filing History
Every role Leonard Osser has reported on a Form 4, reconstructed from the filings themselves - reporting insiders must state their relationship to the issuer (officer title, director seat, or 10% ownership) on every filing.
- 10% Owner at Nexalin Technology, Inc. (NXL) - 1 filing, 2025
- Director at MILESTONE SCIENTIFIC INC. (MLSS) - 1 filing, 2024
Recent Transactions
| Date | Ticker | Company | Code | Shares | Price | Value |
|---|---|---|---|---|---|---|
| 2025-09-29 | NXL | Nexalin Technology, Inc. | A - Grant or award | 83.3K | $0.00 | |
| 2024-10-23 | MLSS | MILESTONE SCIENTIFIC INC. | S - Open-market sale | 108.0K | $0.93 | $100K |
Most Active Insiders Right Now
Leonard Osser has no recent co-filers at the same companies, so here are the insiders with the largest open-market activity across the market in the last 90 days.
- MetLife Investment Management, LLC - $1600000.00B of FINS open-market activity in the last 90 days
- Magnetar Financial LLC - $16357.48B of CRWV open-market activity in the last 90 days
- Marianne Okland - $18.46B of STNG open-market activity in the last 90 days
- VisionWave Holdings, Inc. - $14.13B of SVRE open-market activity in the last 90 days
- Vanessa Allen Sutherland - $7.44B of PSX open-market activity in the last 90 days
- AI Alpine (Luxembourg) S.a.r.l. - $2.69B of INIO open-market activity in the last 90 days
More Notable Insiders
Other corporate insiders with significant SEC Form 4 track records on InsiderAlpha:
- Sam Levinson
- Paul S. Levy
- Liberty 77 Capital L.P.
- LIBERTY MUTUAL HOLDING CO
- Alfred Lin
- Lincoln Financial Investments Corp
- LINCOLN NATIONAL LIFE INSURANCE CO /IN/
- Adam C. Lipson
Frequently Asked Questions
Who is Leonard Osser?
Leonard Osser is a beneficial owner of more than 10% of Nexalin Technology, Inc. (NXL), as disclosed in SEC ownership filings. SEC records also connect Osser to MILESTONE SCIENTIFIC INC. (MLSS). Osser has reported 2 insider filings with the SEC since 2024. The most recent filing was in September 2025.…
Has Leonard Osser been buying or selling stock?
Recorded transactions: 0 open-market purchases and 1 open-market sale ($100K) across all tracked filings.
Where can I see all of Leonard Osser'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.
Learn More
Open the live Leonard Osser profile on InsiderAlpha for real-time alerts, AI-scored trade ideas, and full transaction history.