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

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * IORDANOU CONSTANTINE   2. Issuer Name and Ticker or Trading Symbol ARCH CAPITAL GROUP LTD. [ACGL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chairman & CEO (Last) (First) (Middle) C/O ARCH CAPITAL GROUP LTD., WATERLOO HOUSE,100 PITTS BAY ROAD 3. Date of Earliest Transaction (Month/Day/Year) 12/14/2017 (Street) PEMBROKE, D0 HM 08 4. If Amendment, Date 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 (City) (State) (Zip) 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 Common Shares, $.0033 par value per share 12/14/2017   M(2)   39,753 A (1) 147,078 D   Common Shares, $.0033 par value per share               201,676 I By 2015 GRAT Common Shares, $.0033 par value per share               3,297 I By Limited Liability Company Series C Non-Cumulative Preferred Shares (non-convertible)               1,704 D   Series C Non-Cumulative Preferred Shares (non-convertible)               520 I By spouse

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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 Underlying Securities (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 of Derivative Security: 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

Restricted Share Units

(1)

12/14/2017

M

39,753

(2)

(2)

Common Shares, $.0033 par value per share

39,753

$ 0

13,251

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
IORDANOU CONSTANTINE C/O ARCH CAPITAL GROUP LTD. WATERLOO HOUSE,100 PITTS BAY ROAD PEMBROKE, D0 HM 08	X		Chairman & CEO

Signatures

/s/ Constantine Iordanou		12/19/2017
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	The restricted share units converted into common shares on a one-for-one basis.
(2)	Subject to the applicable award agreement, as amended, the restricted share units vested in four equal annual installments on February 20 in each of 2003, 2004, 2005 and 2006. The award agreement, as amended, provides that the restricted share units will be settled in common shares after the termination of Mr. Iordanou's employment or, if earlier, no later than December 31, 2017 as required by Section 457A of the Internal Revenue Code.

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