Sec Form 4 Filing - Peterson Susan Gayle @ MB FINANCIAL INC /MD - 2013-03-12

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 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 Peterson Susan Gayle 2. Issuer Name and Ticker or Trading Symbol MB FINANCIAL INC /MD [ MBFI] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner _____ Officer (give title below) X __ Other (specify below) Exec. Officer of Subsidiary (Last) (First) (Middle) C/O MB FINANCIAL, INC., 6111 NORTH RIVER ROAD 3. Date of Earliest Transaction (MM/DD/YY) 03/12/2013 (Street) ROSEMONT, IL60018 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 Stock 03/12/2013 S 2,700 D $ 23.844 62,004 D Common Stock 03/12/2013 S 500 D $ 23.841 61,504 D Common Stock 03/12/2013 S 500 D $ 23.852 61,004 D Common Stock 03/12/2013 S 500 D $ 23.851 60,504 D Common Stock 3,997 I By 401(k) Plan Common Stock 9,890 I By Deferred Comp Plan

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 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 Stock Option (Right to Buy) $ 40 07/25/2011( 1 ) 07/25/2017 Common Stock 4,856 4,856 D Stock Option (Right to Buy) $ 32.89 07/25/2011( 1 ) 07/25/2017 Common Stock 5,942 5,942 D Stock Option (Right to Buy) $ 29 06/25/2012( 1 ) 06/25/2018 Common Stock 13,118 13,118 D Stock Option (Right to Buy) $ 24.65 06/25/2012( 1 ) 06/25/2018 Common Stock 16,068 16,068 D Stock Option (Right to Buy) $ 20.4 08/29/2013( 2 ) 08/29/2022 Common Stock 4,071 4,071 D Performance Share Units $ 0 ( 3 ) ( 3 ) Common Stock 4,682 4,682 D Restricted Stock Units $ 0 ( 4 ) ( 4 ) Common Stock 542 542 D Stock Option (Right to Buy) $ 32.6 08/25/2006( 5 ) 01/27/2014 Common Stock 3,101 3,101 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Peterson Susan Gayle C/O MB FINANCIAL, INC. 6111 NORTH RIVER ROAD ROSEMONT, IL60018 Exec. Officer of Subsidiary Signatures /s/ Doria L. Koros, attorney-in-fact for Ms. Peterson 03/12/2013 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Grant to reporting person of option to purchase shares of common stock under Issuer's Amended and Restated Omnibus Incentive Plan. The option is 100% vested. ( 2 )Grant to reporting person of option to purchase shares of common stock under Issuer's Amended and Restated Omnibus Incentive Plan. The option vests ratably over 4 years (25% per year). ( 3 )Performance based vesting ( 4 )Transaction represents the grant of restricted stock units to the reporting person equal to 542 shares of common stock under Issuer's Am ended and Restated Omnibus Incentive Plan. The restricted stock units will vest ratably over 2 years (50% per year). ( 5 )Received in the Merger in exchange for an option to purchase 3,000 shares of FOBB common stock at an exercise price of $33.70 per share.

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).

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