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 * MARCUCCILLI JAMES C   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 _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 127 WEST BERRY STREET 3. Date of Earliest Transaction (Month/Day/Year) 06/01/2011 (Street) FORT WAYNE, IN 46802 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

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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

Deferred Stock Units (1)

$ 0

06/01/2011

06/01/2011

A

5,264

(2)

(2)

Common Stock (3)

5,264 (3)

$ 0

5,264 (4)

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
MARCUCCILLI JAMES C 127 WEST BERRY STREET FORT WAYNE, IN 46802	X

Signatures

James C. Marcuccilli		06/03/2011
**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)	Pursuant to registrant's 2006 Equity Incentive Plan, as amended, in respect to the reporting person's continuing service as a non-employee director and as a portion of his annual retainer, the reporting person on June 1 was granted an exempt award of Deferred Stock Units ("DSUs"). The number of DSUs granted was determined by dividing $90,000 by the closing price of registrant's common stock on the day preceding the grant date.
(2)	The reporting person, by prior election, chose to receive his common stock, when converted from DSUs, at the expiration of one year following the reporting person's termination of service as a director.
(3)	Each whole DSU represents registrant's unsecured and unfunded obligation, upon the expiration of the reporting person's deferral period election, to convert and issue to the reporting person one share of registrant's common stock for each DSU. The DSUs are 100% vested on the grant date.
(4)	The balance shown in Column 9 includes any additional DSUs allocated to the reporting person by virtue of dividends issued on registrant's common stock underlying each related DSU prior to conversion.

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