How are NovaBridge Biosciences ADSs related to its ordinary shares?

NovaBridge Biosciences states that its ordinary shares may be represented by American Depositary Shares (ADSs), with each 10 ADSs representing 23 ordinary shares. This ratio explains how insider holdings and transactions in ADS form correspond to the underlying ordinary share count.

RSU tax sale by NovaBridge Biosciences (NBP) director Cao Wuxiong

Filing Impact

(Neutral)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

NovaBridge Biosciences director and officer Cao Sean Wuxiong reported an open-market sale of ADSs tied to equity compensation. He sold 9,304 American Depositary Shares (ADSs), representing approximately 21,399 ordinary shares, at a price expressed in ADS terms of $1.99. According to the footnotes, this sale was made in connection with the partial vesting of a restricted stock unit award on January 31, 2026, solely to cover tax withholding obligations related to that vesting. Following the transaction, he holds 35,073 ordinary shares, represented by 15,249 ADSs, indicating this was a routine tax-related disposition rather than a full exit.

Insider Trade Summary

Net Seller: 21,399 shares ($42,584)

Net Sell 1 txn

Insider Cao Sean Wuxiong

Role See Remarks

Sold 21,399 shs ($43K)

Type	Security	Shares	Price	Value
Sale	Ordinary Shares	21,399	$1.99	$43K

Holdings After Transaction: Ordinary Shares — 35,073 shares (Direct, null)

Footnotes (1)

The Ordinary Shares may be represented by American Depositary Shares ("ADS"). Each 10 ADSs represent 23 Ordinary Shares of the Issuer. The reporting person sold 9,304 ADSs representing approximately 21,399 ordinary shares in connection with the partial vesting of a restricted stock unit award on January 31, 2026, solely to satisfy tax withholding obligations incurred in connection with the vesting. Price expressed in terms of ADSs. The reported securities are represented by 15,249 ADSs.

Key Figures

ADSs sold: 9,304 ADSs Ordinary shares represented by ADSs sold: approximately 21,399 ordinary shares Sale price per ADS: $1.99 per ADS +4 more

7 metrics

ADSs sold 9,304 ADSs Open-market sale linked to RSU vesting

Ordinary shares represented by ADSs sold approximately 21,399 ordinary shares Underlying shares for 9,304 ADSs

Sale price per ADS $1.99 per ADS Price expressed in terms of ADSs

ADS-to-ordinary-share ratio 10 ADSs represent 23 ordinary shares Company’s stated ADS ratio

Shares after transaction 35,073 ordinary shares Total shares following transaction

ADSs after transaction 15,249 ADSs Reported securities represented by ADSs

RSU vesting date January 31, 2026 Partial vesting triggering tax obligations

Key Terms

American Depositary Shares, ADSs, restricted stock unit award, tax withholding obligations

4 terms

American Depositary Shares financial

"The Ordinary Shares may be represented by American Depositary Shares ("ADS")."

American depositary shares (ADSs) are a way for investors in the United States to buy shares of foreign companies without dealing with international markets directly. They represent ownership in a foreign company's stock and are traded on U.S. stock exchanges, making it easier for American investors to buy, sell, and own parts of companies from around the world.

ADSs financial

"Each 10 ADSs represent 23 Ordinary Shares of the Issuer."

restricted stock unit award financial

"in connection with the partial vesting of a restricted stock unit award on January 31, 2026"

A restricted stock unit award is a promise by a company to give an employee a specified number of company shares at a future date if certain conditions are met, such as staying with the company or hitting performance goals. For investors, these awards matter because they can increase the total number of shares outstanding when converted, diluting existing holders, and they align employees’ incentives with shareholders’ interests much like giving a rising bonus that becomes real only after conditions are satisfied.

tax withholding obligations financial

"solely to satisfy tax withholding obligations incurred in connection with the vesting"

Form 4 Insider Transactions: What Each Field Means →

05/18/2026 - 04:05 PM

SEC Form 4

FORM 4

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

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Cao Sean Wuxiong

(Last)

(First)

(Middle)

C/O NOVABRIDGE BIOSCIENCES,

2440 RESEARCH BOULEVARD, SUITE 400

(Street)

ROCKVILLE

MARYLAND

20850

(City)

(State)

(Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
NovaBridge Biosciences [ NBP ]

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

X	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	See Remarks

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/14/2026

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

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

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

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Ordinary Shares⁽¹⁾	05/14/2026		S⁽²⁾		21,399	D	$1.99⁽³⁾	35,073⁽⁴⁾	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

1. The Ordinary Shares may be represented by American Depositary Shares ("ADS"). Each 10 ADSs represent 23 Ordinary Shares of the Issuer.

2. The reporting person sold 9,304 ADSs representing approximately 21,399 ordinary shares in connection with the partial vesting of a restricted stock unit award on January 31, 2026, solely to satisfy tax withholding obligations incurred in connection with the vesting.

3. Price expressed in terms of ADSs.

4. The reported securities are represented by 15,249 ADSs.

Remarks:

Chief Business Development Officer and Director

	/s/ Xi-Yong (Sean) Fu, as attorney-in-fact	05/18/2026
	** 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 4 (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 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transaction did NovaBridge Biosciences (NBP) report for Cao Sean Wuxiong?

NovaBridge Biosciences reported that director and officer Cao Sean Wuxiong sold 9,304 ADSs, representing about 21,399 ordinary shares. The sale was linked to restricted stock unit vesting and executed to satisfy related tax withholding obligations rather than as a discretionary portfolio decision.

How many NovaBridge Biosciences ADSs and ordinary shares did Cao Sean Wuxiong sell?

Cao Sean Wuxiong sold 9,304 American Depositary Shares (ADSs), which represent approximately 21,399 ordinary shares of NovaBridge Biosciences. The filing notes that each 10 ADSs correspond to 23 ordinary shares under the company’s ADS ratio structure.

Why did Cao Sean Wuxiong sell NovaBridge Biosciences (NBP) ADSs?

The ADS sale was made solely to satisfy tax withholding obligations arising from the partial vesting of a restricted stock unit award on January 31, 2026. Such tax-related transactions are typically mechanical and tied to compensation, rather than signaling a change in the insider’s view of the company.

What is Cao Sean Wuxiong’s remaining NovaBridge Biosciences ownership after the sale?

After the transaction, Cao Sean Wuxiong holds 35,073 ordinary shares of NovaBridge Biosciences, represented by 15,249 ADSs. This remaining position shows he continues to own a meaningful equity stake following the tax-driven sale tied to restricted stock unit vesting.

What price was received for the NovaBridge Biosciences ADSs sold by Cao Sean Wuxiong?

The reported transaction price is $1.99, expressed in terms of ADSs. The filing specifies that this price applies at the ADS level, reflecting the trading unit investors typically see in U.S. markets rather than the underlying ordinary shares directly.