[Form 4] BICYCLE THERAPEUTICS PLC Insider Trading Activity

Rhea-AI Filing Summary

Insider sale tied to RSU tax withholding; small net reduction in holdings. The CEO and director Kevin Lee reported two sell transactions on 10/02/2025 and 10/03/2025 that together disposed of 5,494 ordinary shares at weighted average prices of $8.40 and $8.41 respectively. The filing states these sales were mandated "sell to cover" transactions to satisfy statutory tax withholding on vested restricted stock units and were not discretionary trades. After the transactions, the Reporting Person beneficially owned 475,310 ordinary shares, held directly. The filer certified the usual Section 16 reporting and provided weighted price ranges for the multiple executions.

Positive

• Sale was non-discretionary and executed solely to satisfy statutory tax withholding on vested RSUs
• Reporting person retains a large direct stake of 475,310 ordinary shares after the transactions

Negative

• 5,494 shares were sold in market transactions on 10/02/2025–10/03/2025, creating a modest reduction in holdings
• Weighted average sale prices fell in the low-$8.30–$8.50 range, which may reflect current market pricing pressure

Insights

Corporate Governance Analyst

TL;DR: Tax-driven, non-discretionary sell-to-cover by the CEO; ownership remains sizable.

The reported sales on 10/02/2025 and 10/03/2025 reflect a sell-to-cover mechanism tied to RSU vesting, not an open-market decision to reduce exposure. The filing specifies the transactions were mandated by the award agreement and lists weighted average prices of $8.40 and $8.41, with execution ranges disclosed.

Because the Reporting Person continues to hold 475,310 shares after the transactions, the change is operationally routine and maintains executive alignment with shareholders. Investors may note the timing relative to vesting events; monitor future Form 4 filings for any discretionary sales or pattern changes over the next 3-6 months.

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
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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^*

Lee Kevin

(Last) (First) (Middle)

C/O BICYCLE THERAPEUTICS PLC

BLOCKS A & B, PORTWAY BUILDING

(Street)

CAMBRIDGE X0 CB21 6GS

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
BICYCLE THERAPEUTICS PLC [ BCYC ]

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

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CHIEF EXECUTIVE OFFICER

3. Date of Earliest Transaction (Month/Day/Year)
10/02/2025

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

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 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)
			Code	V	Amount	(A) or (D)	Price
Ordinary Shares	10/02/2025		S		2,263(1)	D	$8.4(2)	478,541	D
Ordinary Shares	10/03/2025		S		3,231(1)	D	$8.41(3)	475,310	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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Represents the number of shares required to be sold to cover the statutory tax withholding obligations in connection with the vesting and settlement of restricted stock units. This sale is mandated by the Reporting Person's award agreement that requires the satisfaction of minimum statutory tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary sale by the Reporting Person.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $8.31 to $8.45 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2) and (3).

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $8.40 to $8.50 inclusive.

	/s/ Travis Thompson, Attorney-in-Fact	10/06/2025
	** 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.

FAQ

What did Bicycle Therapeutics (BCYC) insider Kevin Lee sell?

The filing reports the sale of 5,494 ordinary shares via two transactions on 10/02/2025 and 10/03/2025.

Why were the BCYC shares sold by the reporting person?

The sales were sell-to-cover transactions required to satisfy statutory tax withholding on vested restricted stock units and were not discretionary.

At what prices were the BCYC shares sold?

Weighted average prices were reported at $8.40 (range $8.31–$8.45) and $8.41 (range $8.40–$8.50).

How many BCYC shares does Kevin Lee own after the transactions?

After the reported transactions, the Reporting Person beneficially owned 475,310 ordinary shares.

Were these transactions part of a 10b5-1 plan?

The filing does not indicate that the transactions were made under a 10b5-1 plan; it states they were mandated by the award agreement for tax withholding.