Ownership Submission
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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(Print or Type Responses)
1. Name and Address of Reporting Person *
BUSSE KEITH E
   2. Issuer Name and Ticker or Trading Symbol
STEEL DYNAMICS INC [STLD] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Chairman and CEO
(Last)
(First)
(Middle)
7575 W. JEFFERSON BLVD.		 3. Date of Earliest Transaction (Month/Day/Year)
12/14/2009
(Street)

FORT WAYNE, IN 46804		 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 Stock 12/14/2009   S   10,000 D $ 18.12 1,417,014 (1) D  
Common Stock 12/14/2009   S   10,000 D $ 18.14 1,407,014 D  
Common Stock 12/14/2009   S   10,000 D $ 18.16 1,397,014 D  
Common Stock 12/14/2009   S   10,000 D $ 18.18 1,387,014 D  
Common Stock 12/14/2009   S   10,533 D $ 18.19 1,376,481 D  
Common Stock 12/14/2009   S   75,000 D $ 18.2 1,301,481 D  
Common Stock 12/14/2009   S   30,548 D $ 18.22 1,270,933 D  
Common Stock 12/14/2009   S   25,000 D $ 18.23 1,245,933 D  
Common Stock 12/14/2009   S   20,000 D $ 18.24 1,225,933 D  
Common Stock 12/14/2009   S   11,340 D $ 18.25 1,214,593 D  
Common Stock 12/14/2009   S   10,000 D $ 18.26 1,204,593 D  
Common Stock 12/14/2009   S   3,160 D $ 18.27 1,201,433 D  
Common Stock 12/14/2009   S   10,000 D $ 18.28 1,191,433 D  
Common Stock 12/14/2009   S   10,317 D $ 18.3 1,181,116 D  
Common Stock 12/14/2009   S   10,000 D $ 18.32 1,171,116 D  
Common Stock 12/14/2009   S   10,000 D $ 18.34 1,161,116 D  
Common Stock 12/14/2009   S   100 D $ 18.36 1,161,016 D  
Common Stock 12/15/2009   S   5,000 D $ 18.1 1,156,016 D  
Common Stock 12/15/2009   S   5,000 D $ 18.12 1,151,016 D  
Common Stock 12/15/2009   S   10,000 D $ 18.15 1,141,016 D  
Common Stock 12/15/2009   S   7,870 D $ 18.17 1,133,146 D  
Common Stock 12/15/2009   S   2,130 D $ 18.18 1,131,016 D  
Common Stock 12/15/2009   S   100 D $ 18.2 1,130,916 D  
Common Stock 12/15/2009   S   9,900 D $ 18.21 1,121,016 D  
Common Stock 12/15/2009   S   5,000 D $ 18.22 1,116,016 D  
Common Stock               600,000 I See footnote (2)

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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

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
BUSSE KEITH E
7575 W. JEFFERSON BLVD.
FORT WAYNE, IN 46804		   X     Chairman and CEO  

Signatures

 Keith E. Busse   12/16/2009
**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) Reflects corrected aggregate share total carried over from Column 5 of Reporting Person's Form 4, filed December 15, 2009, (a) for the effect of Issuer's March 19, 2008 2:1 stock split inadvertently not previously applied to certain unvested portions of prior stock bonus awards, and (b) to properly reflect a portion of Reporting Person's deemed holdings as "Indirect," as more fully explained in footnote (2).
(2) Reflects shares Reporting Person previously contributed to and which are held by the Busse Family Investment Company, LLC, formed April 12, 2007. Reporting Person holds no sole or shared voting or investment power over such shares, such authority being vested exclusively in a board of managers of which the Reporting Person is not a member. Reporting Person disclaims all beneficial ownership of such shares, which are nonetheless being reported herein because of Reporting Person's possible pecuniary interest in a portion thereof.

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