MBX MBX Biosciences, Inc.
Price Chart
Executive Summary
Former officer Richard Bartram filed a Form 144 notice of intent to sell 10,000 MBX shares (~$379,562 at filing). The shares are sourced from vested stock options granted in 2022 and 2023. Bartram has sold shares in five separate transactions totaling ~36,484 shares over the past two months, indicating a pattern of consistent monetization rather than a one-off event.
Actionable Insight
This is a routine insider monetization filing by a former officer with a consistent selling pattern. The dollar amount is small relative to market cap. No material read-through for the stock. Monitor for any acceleration in selling volume or additional insider filings ahead of upcoming catalysts.
Key Facts
- Former officer Richard Bartram filed Form 144 to sell 10,000 shares of common stock.
- Estimated aggregate value of the proposed sale is $379,562.50.
- Shares to be sold are from vested stock options granted on 04/20/2022 (2,500 shares), 11/07/2022 (2,500 shares), and 08/15/2023 (5,000 shares).
- Bartram has sold shares in five separate transactions since March 2026, totaling approximately 36,484 shares.
- The filing was made on 05/08/2026 and the proposed sale is for the open market on NASDAQ.
Financial Impact
Proposed sale of $379,562.50, representing approximately 0.02% of MBX's $1.7B market cap.
Risk Factors
- Insider selling pattern could indicate lack of confidence, though the amounts are small relative to market cap.
- Form 144 is an intent to sell; the actual sale may not occur.
Market Snapshot
Documents Analyzed
This report is based on 3 SEC documents filed with EDGAR.
| Document | Accession Number |
|---|---|
| 144 Filing (Primary) | 0001959173-26-003419 |
| Document: 0001959173-26-003419-index.html | 0001959173-26-003419 |
| Document: 0001959173-26-003419.txt | 0001959173-26-003419 |
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
|
Jun 9, 2026
today
|
144
| $29.80 awaiting T+5 | awaiting T+5 | — | $29.00 (+2.68%) |
|
Jun 5, 2026
4d ago
|
8-K
| $30.59 awaiting T+5 | awaiting T+5 | — | $29.00 (−5.20%) |
|
May 11, 2026
29d ago
|
144
| $40.08 $30.98 | ▲ +22.70% | ▲ +22.62% | $29.00 (+27.64%) |
|
May 11, 2026
29d ago
|
Press Release
| $40.08 $30.98 | ▼ −22.70% | ▼ −22.62% | $29.00 (−27.64%) |
|
May 8, 2026
4w ago
|
144
| $40.97 $35.36 | ▼ −13.68% | ▼ −15.15% | $29.00 (−29.21%) |
|
May 7, 2026
4w ago
|
144
| $34.71 $37.50 | ▲ +8.04% | ▲ +6.53% | $29.00 (−16.45%) |
|
May 7, 2026
4w ago
|
8-K
| $34.71 $37.50 | ▲ +8.04% | ▲ +6.53% | $29.00 (−16.45%) |
|
May 6, 2026
4w ago
|
144
| $32.12 $36.98 | ▲ +15.13% | ▲ +14.00% | $29.00 (−9.71%) |
|
May 6, 2026
5w ago
|
Insider Cluster
| $40.08 $30.98 | ▼ −22.70% | ▼ −22.62% | $29.00 (−27.64%) |
|
May 1, 2026
5w ago
|
144
| $29.78 $34.71 | ▼ −16.55% | ▼ −14.21% | $29.00 (+2.62%) |
US Market Status
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