Inhibrx Biosciences, Inc. (INBX) insider trading
Inhibrx Biosciences, Inc. insiders have made 4 open-market purchases worth $2.8M since Sep 17, 2026, by 2 different insiders. The latest: Mark Lappe (CEO) bought $849k, filed Oct 14, 2026, scored 43 out of 100. The biggest: $999k by Mark Lappe, filed Sep 28, 2026. 1 buy in the last year came within ten days of another insider's: a cluster, one of the stronger patterns in the research.
Follow INBX, freeOpen the live feed
A free account gets an alert the minute a new buy or sale is filed.
Insider purchases
| Filed | Insider | Stake | Score | Bought | 1 week | 1 month |
|---|---|---|---|---|---|---|
| Oct 14 Form 4 (opens sec.gov) |
Mark LappeCEOCEO | +1% stake | 43 | $849k 10,040 at $84.56 |
+7.3% | waiting |
| Sep 28 Form 4 (opens sec.gov) |
Mark LappeCEO · 2 insiders buyingCEO · 2 insiders buying | +1% stake | 55 | $999k 10,000 at $99.88 |
−10.9% | −29.7% |
| Sep 23 Form 4 (opens sec.gov) |
Jon Faiz KayyemDirectorDirector · 2 insiders buying | +1% stake | 45 | $500k 5,000 at $100.00 |
−2.5% | −11.7% |
| Sep 17 Form 4 (opens sec.gov) |
Jon Faiz KayyemDirectorDirector | +1% stake | 33 | $500k 5,000 at $100.00 |
−8.9% | −17.9% |
Track record (hypothetical): a week after the filing, these buys averaged −3.7% (25% up, 4 measured); a month after, −19.8% (0% up, 3 measured).
Insider sales
1 open-market sale on record
| Filed | Insider | Sold |
|---|---|---|
| Sep 15 Form 4 (opens sec.gov) |
Kimberly ManhardDirector | $164k 1,500 at $109.03 · 17% of holdings |
Most insider sales are planned in advance or made for personal reasons, so a sale says less than a buy.
Investors with more than 5% of INBX (13D and 13G)
| Filed | Investor | Kind | Stake |
|---|---|---|---|
| Oct 28 13G/A | BANK OF AMERICA CORP /DE/ | Passive | 2.4% |
A 13D is filed by an investor who may push for change; a 13G by a passive one.
Insiders who bought INBX
- Mark Lappe CEO
- Jon Faiz Kayyem Director
Questions
Are insiders buying INBX stock?
Yes. In the last 90 days, 4 open-market purchases were filed, worth $2.8M, against $164k of open-market sales.
Who bought INBX stock most recently?
Mark Lappe, CEO, bought 10,040 shares for $849k (Form 4 (opens sec.gov), filed Oct 14, 2026).
How does InsiderBeacon score an insider buy?
Out of 100, from who bought, how much their stake grew, the size of the trade, whether other insiders bought within ten days, where the price sat in its 52-week range, and whether it was a first or a routine buy. The score is fixed when the filing arrives. The formula and the research behind it.
Insiders are also buying, same industry
Data as of Oct 14, 2026, from SEC EDGAR Form 4 filings: open-market purchases (code P) of $25,000 or more, and open-market sales. Every row links to its filing. Scores summarise what a filing says (how the score works); outcomes are hypothetical, from the first close after the filing, and past results don't predict future ones. Disclaimer