Sec Form 4 Filing - BLOCK ARTHUR R @ COMCAST CORP - 2012-08-20

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 BLOCK ARTHUR R 2. Issuer Name and Ticker or Trading Symbol COMCAST CORP [ CMCSA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) SVP, GC and Secretary (Last) (First) (Middle) ONE COMCAST CENTER 3. Date of Earliest Transaction (MM/DD/YY) 08/20/2012 (Street) PHILADELPHIA, PA19103 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 Class A Common Stock 08/20/2012 M 50,550 A $ 25.44 79,386 D Class A Common Stock 08/20/2012 M 42,540 A $ 18.34 121,926 D Class A Common Stock 08/20/2012 M 21,150 A $ 14.54 143,076 D Class A Common Stock 08/20/2012 M 14,850 A $ 18.98 157,926 D Class A Common Stock 08/20/2012 M 7,500 A $ 19.92 165,426 D Class A Common Stock 08/20/2012 M 5,625 A $ 18.08 171,051 D Class A Common Stock 08/20/2012 F 4,048 D $ 34.02 167,003 D Class A Common Stock 08/20/2012 F 5,639 D $ 34.02 161,364 D Class A Common Stock 08/20/2012 F 10,919 D $ 34.02 150,445 D Class A Common Stock 08/20/2012 F 13,898 D $ 34.02 136,547 D Class A Common Stock 08/20/2012 F 30,798 D $ 34.02 105,749 D Class A Common Stock 08/20/2012 F 42,916 D $ 34.02 62,833 D Class A Special Common Stock 08/20/2012 M 5,625 A $ 15.8933 40,220 D Class A Special Common Stock 08/20/2012 S 15,110 D $ 33.1172 ( 1 ) 25,110 D Class A Special Common Stock 08/20/2012 G V 787 A $ 0 9,878 I By Daughter Class A Special Common Stock 08/20/2012 G V 787 A $ 0 10,115 I By Son

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 Option to Purchase $ 18.08 08/20/2012 M 5,625 ( 2 ) 02/25/2013 Class A Common Stock 5,625 $ 18.08 5,625 D Option to Purchase $ 19.92 08/20/2012 M 7,500 ( 3 ) 03/07/2014 Class A Common Stock 7,500 $ 19.92 15,000 D Option to Purchase $ 18.34 08/20/2012 M 42,540 ( 4 ) 03/25/2020 Class A Common Stock 42,540 $ 0 99,260 D Option to Purchase $ 25.44 08/20/2012 M 50,550 03/16/2008( 5 ) 03/15/2017 Class A Common Stock 50,550 $ 25.44 16,850 D Option to Purchase $ 14.54 08/20/2012 M 21,150 03/27/2010( 6 ) 03/26/2019 Class A Common Stock 21,150 $ 14.54 77,550 D Option to Purchase $ 18.98 08/20/2012 M 14,850 03/28/2009( 7 ) 03/27/2018 Class A Common Stock 14,850 $ 18.98 39,600 D Option to Purchase $ 15.8933 08/20/2012 M 5,625 ( 8 ) 10/26/2012 Class A Special Common Stock 5,625 $ 15.8933 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other BLOCK ARTHUR R ONE COMCAST CENTER PHILADELPHIA, PA19103 SVP, GC and Secretary Signatures Arthur R. Block, Attorney-in-fact 08/21/2012 Signature of Reporting Person Date

Explanation of Responses:

( 1 )This transaction was executed in multiple trades at prices ranging from $33.10 to $33.14. The price reported above reflects the weighted-average price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected. ( 2 )The date of grant was February 26, 2003 and the shares vest as follows: 32.5% vests on the 2nd anniversary of the date of grant, an additional 16.25% vests on each of the 3rd, 4th and 5th anniversaries of the date of grant, and an additional 3.75% vests on each of the 6th, 7th, 8th, 9th and 9.5th anniversaries of the date of grant. ( 3 )As to 50% of the shares subject to this option, the shares vest in installments of 40%, 20%, 20% and 20% on the 2nd, 3rd,4th and 5th anniversaries of the date of grant, respectively; and as to the other 50% of the shares subject to this option, the shares vest in installments of 20%, 10%, 10%, 10%, 10%, 10%, 10%, 10% and 10% on the 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, and 9.5th anniversaries of the date of grant, respectively. ( 4 )The date of grant was March 26, 2010, and the shares vest as follows: 30% vests on the 2nd anniversary of the date of grant, an additional 15% vests on each of the 3rd, 4th and 5th anniversaries of the date of grant, and an additional 5% vests on each of the 6th, 7th, 8th, 9th and 9.5th anniversaries of the date of grant. ( 5 )The date of grant was March 16, 2007, and the shares vest as follows: 30% vests on the 2nd anniversary of the date of grant; an additional 15% vests on each of the 3rd, 4th and 5th anniversaries of the date of grant; and an additional 5% vests on each of the 6th, 7th, 8th, 9th and 9.5th anniversaries of the date of grant. ( 6 )The date of grant was March 27, 2009, and the shares vest as follows: 30% vests on the 2nd anniversary of the date of grant; an additional 15% vests on each of the 3rd, 4th and 5th anniversaries of the date of grant; and an additional 5% vests on each of the 6th, 7th, 8th, 9th and 9.5th anniversaries of the date of grant. ( 7 )The date of grant was March 28, 2008, and the shares vest as follows: 30% vests on the 2nd anniversary of the date of grant; an additional 15% vests on each of the 3rd, 4th and 5th anniversaries of the date of grant; and an additional 5% vests on each of the 6th, 7th, 8th, 9th and 9.5th anniversaries of the date of grant. ( 8 )The date of grant was October 28, 2002 and the shares vest as follows: 100% on the 9.5th anniversary of the date of grant.

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