Sec Form 4 Filing - ACKER WILLIAM P @ MECHANICAL TECHNOLOGY INC - 2005-12-30

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 ACKER WILLIAM P 2. Issuer Name and Ticker or Trading Symbol MECHANICAL TECHNOLOGY INC [ MKTY] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner _____ Officer (give title below) X __ Other (specify below) CEO - MTI MFCI (Last) (First) (Middle) 431 NEW KARNER ROAD 3. Date of Earliest Transaction (MM/DD/YY) 12/30/2005 (Street) ALBANY, NY12205 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

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 Options (Right to Buy) $ 2.8 12/30/2005 A( 1 ) 22,563 12/30/2005( 2 ) 07/16/2012 Common Stock 22,563 $ 2.8 22,563 D Stock Options (Right to Buy) $ 2.8 12/30/2005 A( 1 ) 3,077 12/30/2005( 2 ) 10/14/2012 Common Stock 3,077 $ 2.8 3,077 D Stock Options (Right to Buy) $ 2.8 12/30/2005 A( 1 ) 10,014 12/30/2005( 3 ) 03/31/2013 Common Stock 10,014 $ 2.8 10,014 D Stock Options (Right to Buy) $ 2.8 12/30/2005 A( 1 ) 41,264 12/30/2005( 4 ) 03/31/2013 Common Stock 41,264 $ 2.8 41,264 D Stock Options (Right to Buy) $ 2.8 12/30/2005 A( 1 ) 123,142 12/30/2005( 5 ) 12/09/2014 Common Stock 123,142 $ 2.8 123,142 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other ACKER WILLIAM P 431 NEW KARNER ROAD ALBANY, NY12205 CEO - MTI MFCI Signatures By: Cynthia A. Scheuer as Attorney in Fact for 01/03/2006 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents options issued in exchange for MTI Micro options tendered and canceled pursuant to the MTI and MTI Micro November 28, 2005 Exchange Offer. The exchange rate is one (1) MTI option for each two (2) shares of MTI Micro common stock issuable upon exercise of surrendered MTI Micro options, rounded down to the nearest whole share, or if an individual had an MTI Micro option balance in excess of 150,000, then at a rate of one (1) MTI option for each four (4) shares of MTI Micro common stock issuable upon exercise of surrendered MTI Micro options in excess of 150,000. All options were issued with the same vesting schedule and expiration term as the originally issued MTI Micro options. ( 2 )Immediately Vested. ( 3 )5,007 are immediately vested and the remainder vests 50% on 04/01/06 and 04/01/07, respectively. ( 4 )20,632 are immediately vested and the remainder vests 50% on 04/01/06 and 04/01/07, respectively. ( 5 )30,785 are immediately vested and the remainder vests 8.33% per quarter beginning on 01/01/06.

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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