Moleculin Biotech (MBRX) CFO exercises RSUs, uses shares to cover taxes
Rhea-AI Filing Summary
Moleculin Biotech, Inc. Chief Financial Officer Jonathan P. Foster reported routine equity compensation activity involving restricted stock units and related tax withholding. On June 20 and June 22, 2026, restricted stock units converted into a total of 283 shares of common stock at a conversion price of $0.00 per share.
To cover tax obligations on these vestings, 72 shares of common stock were disposed of at prices of $2.88 and $3.12 per share through tax-withholding dispositions, not open-market sales. Following these transactions, Foster directly holds 12,340 shares of common stock and 147,718 derivative securities, which include 100,003 shares of common stock underlying Series E warrants.
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Insider Trade Summary
Net Buyer: 211 shares
Net Buy
6 txns
Insider
Foster Jonathan P.
Role
Chief Financial Officer
| Type | Security | Shares | Price | Value |
|---|---|---|---|---|
| Exercise | Restricted Stock Units | 174 | $0.00 | $0.00 |
| Exercise | Common Stock | 174 | $0.00 | $0.00 |
| Exercise Price or Tax Liability | Common Stock | 41 | $3.12 | $127.92 |
| Exercise | Restricted Stock Units | 109 | $0.00 | $0.00 |
| Exercise | Common Stock | 109 | $0.00 | $0.00 |
| Exercise Price or Tax Liability | Common Stock | 31 | $2.88 | $89.28 |
Holdings After Transaction:
Restricted Stock Units — 147,718 shares (Direct);
Common Stock — 12,340 shares (Direct)
Footnotes (5)
- F1. Restricted stock units convert into common stock on a one-for-one basis.
- F2. Shares withheld for payment of taxes upon vesting of restricted stock unit awards.
- F3. On June 20, 2022, the reporting person was granted 434 restricted stock units, vesting in four equal annual installments beginning on the first anniversary of the grant date.
- F4. On June 22, 2023, the reporting person was granted 693 restricted stock units, vesting in four equal annual installments beginning on the first anniversary of the grant date.
- F5. Includes 100,003 shares of common stock underlying Series E warrants to purchase common stock.
Key Figures
RSU conversions: 283 shares
Tax-withholding shares: 72 shares
Post-transaction common shares: 12,381 shares
+5 more
8 metrics
RSU conversions
283 shares
Restricted stock units converted into common stock on June 20 and 22, 2026
Tax-withholding shares
72 shares
Shares delivered to cover tax obligations at $2.88 and $3.12 per share
Post-transaction common shares
12,381 shares
Common stock directly held by CFO following June 22, 2026 transactions
Post-transaction derivatives
147,718 securities
Total derivative securities held after RSU conversions
Series E warrant underlying shares
100,003 shares
Common stock underlying Series E warrants included in holdings
Tax-withholding price 1
$2.88/share
Price used for 31-share tax-withholding disposition on June 20, 2026
Tax-withholding price 2
$3.12/share
Price used for 41-share tax-withholding disposition on June 22, 2026
RSU grant 2023
693 RSUs
Grant on June 22, 2023, vesting in four equal annual installments
Key Terms
Restricted stock units, tax-withholding disposition, derivative security, Series E warrants, +1 more
5 terms
Restricted stock units financial
"Restricted stock units convert into common stock on a one-for-one basis."
Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.
tax-withholding disposition financial
"Payment of exercise price or tax liability by delivering securities."
A tax-withholding disposition is an event or transaction—such as selling or transferring securities, exercising options, or receiving compensation—that triggers a requirement to hold back part of the payment and remit it to tax authorities. It matters to investors because it reduces the cash they receive immediately and can change the timing and amount of taxable income, like a cashier taking a portion of your sale proceeds to pay taxes before you get the rest.
derivative security financial
"Exercise or conversion of derivative security."
A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.
Series E warrants financial
"Includes 100,003 shares of common stock underlying Series E warrants to purchase common stock."
vests in four equal annual installments financial
"Vesting in four equal annual installments beginning on the first anniversary of the grant date."
FAQ
What insider transactions did Moleculin Biotech (MBRX) report for its CFO?
Moleculin Biotech CFO Jonathan P. Foster exercised restricted stock units and had shares withheld for taxes. In June 2026, 283 RSUs converted into common shares, while 72 shares were disposed of to satisfy tax obligations related to these vestings, rather than through open-market sales.
What are Jonathan P. Foster’s holdings in Moleculin Biotech (MBRX) after these Form 4 transactions?
After the transactions, the CFO directly holds 12,381 shares of Moleculin Biotech common stock. He also holds 147,718 derivative securities, which the filing notes include 100,003 shares of common stock underlying Series E warrants, providing additional potential equity exposure.
Were Moleculin Biotech (MBRX) CFO’s Form 4 transactions open-market buys or sales?
The reported transactions were RSU conversions and tax-withholding dispositions, not open-market trades. Code M entries reflect derivative exercises at $0.00 per share, while code F entries show shares delivered to pay taxes on vesting, rather than discretionary market purchases or sales.
AI-generated analysis. How Rhea-AI works. Not financial advice.
