Bambusa Therapeutics CFO reports option on 440K shares

The option's vesting is conditioned on continued employment, with 25% scheduled for the one-year anniversary.

Accepted by SEC EDGAR 10/29/2026 - 04:28 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Bambusa Therapeutics, Inc. Chief Financial Officer Jonathan I. Lieber reported a directly held stock option covering 440,282 common shares, with an exercise price of $13.57 per share and an expiration date of September 17, 2036. Subject to his continued employment through each applicable date, 25% of the option shares vest on the one-year anniversary of September 15, 2026, and 1/48 vests monthly thereafter.

Insider Trade Summary

Holdings reported, no transactions

Holdings

Insider Lieber Jonathan I

Role Chief Financial Officer

Type	Security	Shares	Price	Value
Holding	Stock Option (right to buy) F1	--	--	--

Holdings: Stock Option (right to buy) — 440,282 contracts (Direct)

Footnotes (1)

1. F1. Subject to the Reporting Person continuing to be an Employee (as defined in the Issuer's 2024 Stock Plan) through each applicable date, twenty five percent (25%) of the shares subject to the option shall vest on the one (1) year anniversary of the Vesting Commencement Date, and one forty-eighth (1/48th) of the shares subject to the option shall vest each month thereafter on the same day of the month as the Vesting Commencement Date (and if there is no corresponding day, on the last day of the month). "Vesting Commencement Date" shall mean September 15, 2026.

Key Figures

Common shares underlying option: 440,282 shares Exercise price: $13.57 per share Option expiration: September 17, 2036 +3 more

6 metrics

Common shares underlying option 440,282 shares Directly held stock option

Exercise price $13.57 per share Stock option

Option expiration September 17, 2036 Stock option

Initial vesting tranche 25% of shares subject to the option Vests on the one-year anniversary of September 15, 2026, subject to continued employment

Monthly vesting 1/48 of shares subject to the option Each month after the initial vesting date, subject to continued employment

Vesting commencement date September 15, 2026 Defined in the option footnote

Key Terms

Stock Option (right to buy), Vesting Commencement Date, 2024 Stock Plan

3 terms

Stock Option (right to buy) financial

"Stock Option (right to buy)"

Vesting Commencement Date financial

""Vesting Commencement Date" shall mean September 15, 2026."

The vesting commencement date is the starting point when an employee begins earning ownership rights to their promised benefits, such as stock options or retirement contributions. Think of it like the day a savings account is opened—only after this date do the benefits start to grow and become fully available over time. It matters to investors because it marks when the clock begins ticking toward full ownership, affecting the timing and value of these benefits.

2024 Stock Plan financial

"Employee (as defined in the Issuer's 2024 Stock Plan)"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many BBTX shares does Jonathan I. Lieber's stock option cover?

Jonathan I. Lieber, Bambusa Therapeutics' chief financial officer, reported a directly held option covering 440,282 common shares at an exercise price of $13.57 per share; it expires September 17, 2036.

How does vesting work for the BBTX option reported by the CFO?

Subject to continued employment through each applicable date, 25% of the shares subject to the option vest on the one-year anniversary of September 15, 2026. One forty-eighth of the shares vest each month thereafter on the same day of the month as the vesting commencement date, or on the month's last day if there is no corresponding day.

AI-generated analysis. How Rhea-AI works. Not financial advice.

Understanding Insider Trading Forms →

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0104
Estimated average burden
hours per response:			0.5

1. Name and Address of Reporting Person^*

Lieber Jonathan I

(Last) (First) (Middle)

C/O BAMBUSA THERAPEUTICS, INC.

22 BOSTON WHARF ROAD, FLOOR 7

(Street)

BOSTON MASSACHUSETTS 02210

(City) (State) (Zip)

UNITED STATES

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
10/29/2026

3. Issuer Name and Ticker or Trading Symbol
Bambusa Therapeutics, Inc. [ BBTX ]

3a. Foreign Trading Symbol

5. If Amendment, Date of Original Filed (Month/Day/Year)

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	(1)	09/17/2036	Common Stock	440,282	$13.57	D

Explanation of Responses:

1. Subject to the Reporting Person continuing to be an Employee (as defined in the Issuer's 2024 Stock Plan) through each applicable date, twenty five percent (25%) of the shares subject to the option shall vest on the one (1) year anniversary of the Vesting Commencement Date, and one forty-eighth (1/48th) of the shares subject to the option shall vest each month thereafter on the same day of the month as the Vesting Commencement Date (and if there is no corresponding day, on the last day of the month). "Vesting Commencement Date" shall mean September 15, 2026.

Remarks:

Exhibit 24 - Power of Attorney

	/s/ Jonathan I. Lieber	10/29/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 3: SEC 1473 (03-26)