<SUBMISSION>
<ACCESSION-NUMBER>0001047469-07-008880
<TYPE>S-8
<PUBLIC-DOCUMENT-COUNT>3
<FILING-DATE>20071109
<DATE-OF-FILING-DATE-CHANGE>20071109
<EFFECTIVENESS-DATE>20071109
<FILER>
<COMPANY-DATA>
<CONFORMED-NAME>STEEL DYNAMICS INC
<CIK>0001022671
<ASSIGNED-SIC>3312
<IRS-NUMBER>351929476
<STATE-OF-INCORPORATION>IN
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>S-8
<ACT>33
<FILE-NUMBER>333-147271
<FILM-NUMBER>071231228
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>6714 POINTE INVERNESS WAY
<STREET2>SUITE 200
<CITY>FORT WAYNE
<STATE>IN
<ZIP>46804
<PHONE>2604593553
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>6714 POINTE INVERNESS WAY
<STREET2>SUITE 200
<CITY>FORT WAYNE
<STATE>IN
<ZIP>46804
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<DOCUMENT>
<TYPE>S-8
<SEQUENCE>1
<FILENAME>a2180886zs-8.htm
<DESCRIPTION>S-8
<TEXT>
<HTML>
<HEAD>
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<FONT SIZE=3 ><A HREF="#07ZDO46501_1">QuickLinks</A></FONT>
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<P ALIGN="CENTER"><FONT SIZE=2><B>Filed with the Securities and Exchange Commission on November&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;, 2007  </B></FONT></P>

<P ALIGN="RIGHT"><FONT SIZE=2><B> Registration No.&nbsp;333-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</B></FONT></P>

<P><FONT SIZE=2><B> <hr noshade width=100% align=left size=4>
<hr noshade width=100% align=left size=1>  </B></FONT></P>

<P ALIGN="CENTER"><FONT SIZE=5><B>SECURITIES AND EXCHANGE COMMISSION<BR>  </B></FONT><FONT SIZE=2><B>Washington, D.C. 20549  </B></FONT></P>

<HR NOSHADE ALIGN="CENTER" WIDTH="120">
<P ALIGN="CENTER"><FONT SIZE=5><B>FORM S-8<BR>  </B></FONT><FONT SIZE=2><B>REGISTRATION STATEMENT<BR>
UNDER<BR>
THE SECURITIES ACT OF 1933  </B></FONT></P>

<HR NOSHADE ALIGN="CENTER" WIDTH="120">
<P ALIGN="CENTER"><FONT SIZE=5><B>STEEL DYNAMICS,&nbsp;INC.<BR>  </B></FONT><FONT SIZE=2>(Exact name of Registrant as specified in its Articles of Incorporation) </FONT></P>

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<TD WIDTH="32%" ALIGN="CENTER"><FONT SIZE=2><B>Indiana</B></FONT></TD>
<TD WIDTH="2%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="32%" ALIGN="CENTER"><FONT SIZE=2><B>3312</B></FONT></TD>
<TD WIDTH="2%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="32%" ALIGN="CENTER"><FONT SIZE=2><B>35-1929476</B></FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD WIDTH="32%" ALIGN="CENTER"><FONT SIZE=2>(State or other jurisdiction of incorporation)</FONT></TD>
<TD WIDTH="2%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="32%" ALIGN="CENTER"><FONT SIZE=2>(Primary standard industrial<BR>
classification code number)</FONT></TD>
<TD WIDTH="2%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="32%" ALIGN="CENTER"><FONT SIZE=2>(IRS Employer Identification No.)</FONT></TD>
</TR>
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<P ALIGN="CENTER"><FONT SIZE=2><B>6714 Pointe Inverness Way, Suite 200<BR>
Fort Wayne, Indiana 46804<BR>
(260)&nbsp;459-3553<BR>  </B></FONT><FONT SIZE=2>(Address, including zip code and telephone number, including<BR>
area code of Registrant's principal executive offices) </FONT></P>

<HR NOSHADE ALIGN="CENTER" WIDTH="120">
<P ALIGN="CENTER"><FONT SIZE=2><B>2006 Equity Incentive Plan<BR>
Steel Dynamics,&nbsp;Inc. Amended and Restated<BR>
1996 Incentive Stock Option Plan<BR>
Steel Dynamics,&nbsp;Inc. Non-Employee Directors Stock Option Plan<BR>  </B></FONT><FONT SIZE=2>(Full titles of the plans) </FONT></P>

<HR NOSHADE ALIGN="CENTER" WIDTH="120">
<P ALIGN="CENTER"><FONT SIZE=2><B>Keith E. Busse<BR>
President and Chief Executive Officer<BR>
Steel Dynamics,&nbsp;Inc.<BR>
6714 Pointe Inverness Way, Suite 200<BR>
Fort Wayne, Indiana 46804<BR>
(260)&nbsp;459-3553<BR>  </B></FONT><FONT SIZE=2>(Name, address, including zip code, and telephone<BR>
number, including area code, of agent for service) </FONT></P>

<HR NOSHADE ALIGN="CENTER" WIDTH="120">
<P ALIGN="CENTER"><FONT SIZE=2><B><I>Copy to:<BR>  </I></B></FONT><FONT SIZE=2><B>Robert S. Walters, Esq.<BR>
Barrett&nbsp;&amp; McNagny LLP<BR>
215 East Berry Street<BR>
Fort Wayne, Indiana 46802<BR>
(260)&nbsp;423-9551  </B></FONT></P>

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<P ALIGN="CENTER"><FONT SIZE=2><B> CALCULATION OF REGISTRATION FEE  </B></FONT></P>

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<TD COLSPAN=9><HR NOSHADE></TD>
</TR>
<TR VALIGN="BOTTOM">
<TH WIDTH="37%" ALIGN="CENTER"><FONT SIZE=1><B>Title of Each Class of<BR>
Securities to be Registered</B></FONT><BR></TH>
<TH WIDTH="1%"><FONT SIZE=1>&nbsp;</FONT></TH>
<TH WIDTH="15%" ALIGN="CENTER"><FONT SIZE=1><B>Number of Shares<BR>
to be Registered</B></FONT><BR></TH>
<TH WIDTH="1%"><FONT SIZE=1>&nbsp;</FONT></TH>
<TH WIDTH="16%" ALIGN="CENTER"><FONT SIZE=1><B>Proposed Maximum<BR>
Offering Price<BR>
Per Share</B></FONT><BR></TH>
<TH WIDTH="1%"><FONT SIZE=1>&nbsp;</FONT></TH>
<TH WIDTH="16%" ALIGN="CENTER"><FONT SIZE=1><B>Proposed Maximum<BR>
Aggregate Offering<BR>
Price</B></FONT><BR></TH>
<TH WIDTH="1%"><FONT SIZE=1>&nbsp;</FONT></TH>
<TH WIDTH="12%" ALIGN="CENTER"><FONT SIZE=1><B>Amount of<BR>
Registration<BR>
Fee</B></FONT><BR></TH>
</TR>
<TR VALIGN="TOP">
<TD COLSPAN=9><HR NOSHADE></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="37%"><FONT SIZE=2>2006 Equity Incentive Plan Common Stock,<BR>
&nbsp;&nbsp;&nbsp;&nbsp;$.001 par value</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="15%" ALIGN="CENTER"><FONT SIZE=2>6,720,971(2)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="16%" ALIGN="CENTER"><FONT SIZE=2>$51.90(3)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="16%" ALIGN="CENTER"><FONT SIZE=2>$348,818,395(3)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="12%" ALIGN="CENTER"><FONT SIZE=2>$10,709</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD COLSPAN=9><HR NOSHADE></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="37%"><FONT SIZE=2>2006 Equity Incentive Plan Common Stock,<BR>
&nbsp;&nbsp;&nbsp;&nbsp;$.001 par value</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="15%" ALIGN="CENTER"><FONT SIZE=2>730,353(4)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="16%" ALIGN="CENTER"><FONT SIZE=2>$36.84(5)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="16%" ALIGN="CENTER"><FONT SIZE=2>$26,906,205(5)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="12%" ALIGN="CENTER"><FONT SIZE=2>$826</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD COLSPAN=9><HR NOSHADE></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="37%"><FONT SIZE=2>2006 Equity Incentive Plan Common Stock,<BR>
&nbsp;&nbsp;&nbsp;&nbsp;$.001 par value</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="15%" ALIGN="CENTER"><FONT SIZE=2>24,829(6)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="16%" ALIGN="CENTER"><FONT SIZE=2>$51.90(7)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="16%" ALIGN="CENTER"><FONT SIZE=2>$1,288,652(7)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="12%" ALIGN="CENTER"><FONT SIZE=2>$40</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD COLSPAN=9><HR NOSHADE></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="37%"><FONT SIZE=2>Steel Dynamics, Inc. Amended and Restated<BR>
&nbsp;&nbsp;&nbsp;&nbsp;1996 Incentive Stock Option Plan Common<BR>
&nbsp;&nbsp;&nbsp;&nbsp;Stock, $.001 par value</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="15%" ALIGN="CENTER"><FONT SIZE=2>751,817(8)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="16%" ALIGN="CENTER"><FONT SIZE=2>$13.77(9)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="16%" ALIGN="CENTER"><FONT SIZE=2>$10,352,520(9)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="12%" ALIGN="CENTER"><FONT SIZE=2>$318</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD COLSPAN=9><HR NOSHADE></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="37%"><FONT SIZE=2>Steel Dynamics, Inc. Non-Employee Directors<BR>
&nbsp;&nbsp;&nbsp;&nbsp;Stock Option Plan Common Stock, $.001<BR>
&nbsp;&nbsp;&nbsp;&nbsp;par value</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="15%" ALIGN="CENTER"><FONT SIZE=2>36,582(10)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="16%" ALIGN="CENTER"><FONT SIZE=2>$11.08(11)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="16%" ALIGN="CENTER"><FONT SIZE=2>$405,329(11)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="12%" ALIGN="CENTER"><FONT SIZE=2>$12</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD COLSPAN=9><HR NOSHADE></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="37%"><FONT SIZE=2>2006 Equity Incentive Plan Common Stock,<BR>
&nbsp;&nbsp;&nbsp;&nbsp;$.001 par value</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="15%" ALIGN="CENTER"><FONT SIZE=2>56,330(12)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="16%" ALIGN="CENTER"><FONT SIZE=2>$51.90(13)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="16%" ALIGN="CENTER"><FONT SIZE=2>$2,923,527(13)</FONT></TD>
<TD WIDTH="1%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="12%" ALIGN="CENTER"><FONT SIZE=2>$90</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD COLSPAN=9><HR NOSHADE></TD>
</TR>
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<P ALIGN="RIGHT"><FONT SIZE=2><I>(Footnotes on next page)  </I></FONT></P>

<P><FONT SIZE=2><I> <hr noshade width=100% align=left size=1>
<hr noshade width=100% align=left size=4>  </I></FONT></P>

<HR NOSHADE>
<P style='page-break-before:always'></p>
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<DL compact>
<DT style='margin-bottom:-11pt;'><FONT SIZE=2>(1)</FONT></DT><DD><FONT SIZE=2>Pursuant
to Rule&nbsp;416(a) under the Securities Act of 1933, as amended (the </FONT><FONT SIZE=2><B><I>"Securities Act"</I></B></FONT><FONT SIZE=2>), this Registration Statement shall
also cover any additional shares of Registrant's Common Stock (the </FONT><FONT SIZE=2><B><I>"Common Stock"</I></B></FONT><FONT SIZE=2>) that become issuable under the plans by reason of any stock dividend,
stock split, recapitalization or other similar transaction effected without the receipt of consideration which results in an increase in the number of outstanding shares of Registrant's Common Stock.
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(2)</FONT></DT><DD><FONT SIZE=2>Represents
6,777,301 shares of Common Stock reserved for future grant under the 2006 Equity Incentive Plan (the "2006 Plan").
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(3)</FONT></DT><DD><FONT SIZE=2>Estimated
solely for purposes of calculating the registration fee. Pursuant to Rule&nbsp;457(h)(1) under the Securities Act of 1933. The proposed maximum offering price per share,
the proposed maximum aggregate offering price and the amount of the registration fee have been computed on the basis of the average of the high and low prices of Registrant's Common Stock reported on
the Nasdaq Global Select Market on November&nbsp;1, 2007.
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(4)</FONT></DT><DD><FONT SIZE=2>Represents
730,353 shares of Common Stock reserved for issuance upon the exercise of outstanding options granted under the 2006 Plan.
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(5)</FONT></DT><DD><FONT SIZE=2>Estimated
solely for the purpose of calculating the amount of the registration fee pursuant to Rule&nbsp;457(h)(1) and Rule&nbsp;457(c) of the Securities Act of 1933. The proposed
maximum offering price per share, the proposed maximum aggregate offering price for the 730,353 shares of Common Stock reserved for future issuance upon the exercise of options outstanding under the
2006 Plan and the amount of the registration fee have been calculated using a weighted average exercise price for such shares of $36.84 per share based on exercise prices for such shares ranging from
$28.32 to $48.36 per share.
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(6)</FONT></DT><DD><FONT SIZE=2>Represents
24,829 shares of Common Stock issued as restricted stock to non-employee directors pursuant to the 2006 Plan.
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(7)</FONT></DT><DD><FONT SIZE=2>Estimated
solely for purposes of calculating the registration fee pursuant to Rule&nbsp;457(h)(1) under the Securities Act of 1933. The proposed maximum offering price per share,
the proposed maximum aggregate offering price and the amount of the registration fee have been computed on the basis of the average of the high and low prices of Registrant's Common Stock reported on
the Nasdaq Global Select Market on November&nbsp;1, 2007.
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(8)</FONT></DT><DD><FONT SIZE=2>Represents
751,817 shares of Common Stock reserved for issuance upon the exercise of outstanding options granted under the Steel Dynamics,&nbsp;Inc. Amended and Restated 1996
Incentive Stock Option Plan (the "1996 Plan"). The 1996 Plan was terminated in 2006 and no further option grants will be made under the 1996 Plan.
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(9)</FONT></DT><DD><FONT SIZE=2>Estimated
solely for the purpose of calculating the amount of the registration fee pursuant to Rule&nbsp;457(h)(1) and Rule&nbsp;457(c) of the Securities Act of 1933. The proposed
maximum offering price per share, the proposed maximum aggregate offering price for the 751,817 shares of Common Stock reserved for future issuance upon the exercise of options outstanding under the
1996 Plan and the amount of the registration fee have been calculated using a weighted average exercise price for such shares of $13.77 per share based on exercise prices for such shares ranging from
$6.38 to $18.86 per share.
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(10)</FONT></DT><DD><FONT SIZE=2>Represents
36,582 shares of Common Stock reserved for issuance upon the exercise of outstanding options granted under the Steel Dynamics,&nbsp;Inc. Non-Employee
Director Stock Option Plan (the "Director Plan"). The Director Plan was terminated in 2006 and no further option grants will be made under the Director Plan.
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(11)</FONT></DT><DD><FONT SIZE=2>Estimated
solely for the purpose of calculating the amount of the registration fee pursuant to Rule&nbsp;457(h)(1) and Rule&nbsp;457(c) of the Securities Act of 1933. The
proposed maximum offering price per share, the proposed maximum aggregate offering price for the 36,582 shares of Common Stock reserved for future issuance upon the exercise of options outstanding
under the Director Plan and the amount of the registration fee have been calculated using a weighted average exercise price for such shares of $11.08 per share based on exercise prices for such shares
ranging from $6.38 to $18.86 per share.
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(12)</FONT></DT><DD><FONT SIZE=2>Represents
56,330 shares of Common Stock issued as unrestricted stock awards under the 2006 Plan to certain employees of an acquired subsidiary.
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(13)</FONT></DT><DD><FONT SIZE=2>Estimated
solely for purposes of calculating the registration fee. Pursuant to Rule&nbsp;457(h)(1) under the Securities Act of 1933. The proposed maximum offering price per share,
the proposed maximum aggregate offering price and the amount of the registration fee have been computed on the basis of the average of the high and low prices of Registrant's Common Stock reported on
the Nasdaq Global Select Market on November&nbsp;1, 2007. </FONT></DD></DL>
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<A NAME="toc_bc46501_1"> </A>
<BR></FONT><FONT SIZE=2><B>PART I<BR>  Information Required in the Section&nbsp;10(a) Prospectus    <BR>    </B></FONT></P>

<P><FONT SIZE=2><B>Item 1.&nbsp;&nbsp;&nbsp;&nbsp;Plan Information.  </B></FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The documents containing the information specified in this Item 1 will be sent or given to participants as specified by Rule&nbsp;428(b)(1) under the Securities
Act of 1933, as amended (the "</FONT><FONT SIZE=2><I>Securities Act</I></FONT><FONT SIZE=2>"). In accordance with the rules and regulations of the Securities and Exchange Commission (the
"</FONT><FONT SIZE=2><I>Commission</I></FONT><FONT SIZE=2>") and the instructions to Form&nbsp;S-8, such documents are not being filed with the Commission either as part of this
Registration Statement or as prospectuses or prospectus supplements pursuant to Rule&nbsp;424 under the Securities Act. </FONT></P>

<P><FONT SIZE=2><B>Item 2.&nbsp;&nbsp;&nbsp;&nbsp;Registrant Information and Employee Plan Annual Information.  </B></FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The documents containing the information specified in this Item 2 will be sent or given to participants as specified by Rule&nbsp;428(b)(1) under the Securities
Act. In accordance with the rules and regulations of the Commission and the instructions to Form&nbsp;S-8, such documents are not being filed with the Commission either as part of this
Registration Statement or as prospectuses or prospectus supplements pursuant to Rule&nbsp;424 under the Securities Act. </FONT></P>

<P ALIGN="CENTER"><FONT SIZE=2>1</FONT></P>

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<A NAME="toc_de46501_1"> </A>
<BR></FONT><FONT SIZE=2><B>PART II<BR>  Information Required in the Registration Statement    <BR>    </B></FONT></P>

<P><FONT SIZE=2><B>ITEM 3.&nbsp;&nbsp;&nbsp;&nbsp;Incorporation of Documents by Reference.  </B></FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;This registration statement incorporates by reference the documents set forth below that we have previously filed with the Securities and Exchange Commission: </FONT></P>

<UL>
<DL compact>
<DT style='margin-bottom:-11pt;'><FONT SIZE=2>&#149;</FONT></DT><DD><FONT SIZE=2>Annual
Report on Form&nbsp;10-K for the year ended December&nbsp;31, 2006, including information specifically incorporated by reference into the
Form&nbsp;10-K from our definitive proxy statement for our 2007 Annual Meeting of Stockholders filed with the Securities and Exchange Commission on April&nbsp;3, 2007;
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>&#149;</FONT></DT><DD><FONT SIZE=2>Quarterly
Reports on Form&nbsp;10-Q for the quarterly periods ended March&nbsp;31, 2007, June&nbsp;30, 2007 and September&nbsp;30, 2007;
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>&#149;</FONT></DT><DD><FONT SIZE=2>Current
Reports on Form&nbsp;8-K filed March&nbsp;2, 2007 (with respect to Item 7.01); March&nbsp;15, 2007 and April&nbsp;3, 2007 (with respect to Item
8.01); April&nbsp;3, 2007 (with respect to Items 1.01, 2.03 and 8.01); April&nbsp;23, 2007 (with respect to Items 5.02(b) and 5.02(c), as well as Item 8.01; April&nbsp;27, 2007 and
June&nbsp;1, 2007 (with respect to Item 8.01); June&nbsp;18, 2007 (with respect to Items 1.01 and 8.01); June&nbsp;21, 2007 (with respect to Items 2.03 and 8.01); June&nbsp;29, 2007 (with
respect to Item 7.01); July&nbsp;6, 2007 (with respect to Items 2.01 and 8.01); July&nbsp;16, 2007 (with respect to Item 8.01); July&nbsp;24, 2007 (with respect to Item 2.02); August&nbsp;1,
2007 and September&nbsp;4, 2007 (with respect to Item 8.01); September&nbsp;14, 2007 (with respect to Items 2.03 and 8.01); September&nbsp;21, 2007 (with respect to Item 8.01); October&nbsp;3,
2007 (with respect to Items 1.01 and 8.01); October&nbsp;4, 2007 (with respect to Item 7.01); October&nbsp;4, 2007 (with respect to Item 8.01); October&nbsp;18, 2007 (with respect to Item 2.02)
and a current report on Form&nbsp;8-K/A filed November&nbsp;6, 2007 (with respect to Items 2.01, 3.02, 5.01 and 8.01).
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>&#149;</FONT></DT><DD><FONT SIZE=2>The
description of our common stock contained in our Registration Statement on Form&nbsp;8-A, filed with the Securities and Exchange Commission on
November&nbsp;13, 1996. </FONT></DD></DL>
</UL>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;We
also incorporate by reference all other reports that we file with the Securities and Exchange Commission pursuant to Section&nbsp;13(a), 13(c), 14 or 15(d) of the Securities
Exchange Act of 1934, as amended, after the date of this Registration Statement and until we file&nbsp;a post-effective amendment which indicates that all securities offered have been
sold or which deregisters all securities then remaining unsold. </FONT></P>

<P><FONT SIZE=2><B>ITEM 4.&nbsp;&nbsp;&nbsp;&nbsp;Description of Securities.  </B></FONT></P>


<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Not Applicable. </FONT></P>

<P><FONT SIZE=2><B>ITEM 5.&nbsp;&nbsp;&nbsp;&nbsp;INTERESTS OF NAMED EXPERTS AND COUNSEL.  </B></FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Not Applicable. </FONT></P>

<P><FONT SIZE=2><B>ITEM 6.&nbsp;&nbsp;&nbsp;&nbsp;INDEMNIFICATION OF DIRECTORS AND OFFICERS.  </B></FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The Company's Amended and Restated Articles of Incorporation (the "Articles") limit the liability of directors and officers providing that the Company shall
indemnify a person made a party to a proceeding, because that person is or was a director or officer, against liability incurred in the proceeding, as well as expenses (including counsel fees), if the
person's conduct was in good faith, and if he or she reasonably believed, in the case of "official conduct" with the Company, that his or her conduct was in the Company's best interests (or at least
that the conduct was not opposed to the Company's best interests), and, in the case of any criminal proceeding, that the individual either had reasonable cause to believe that the conduct was lawful,
or had no reasonable cause to believe that the </FONT></P>

<P ALIGN="CENTER"><FONT SIZE=2>2</FONT></P>

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<P><FONT SIZE=2>conduct
was unlawful. Indemnification against reasonable expenses incurred by a director or officer is also required in any case in which that person, having been made a party to a proceeding because
he or she was a director or officer, has been wholly successful, on the merits or otherwise, in the defense of such action. These provisions prohibit indemnity if a director or officer is found liable
in a proceeding by the Company (or in a stockholder derivative action on behalf of the Company) against the director or officer, or in connection with a proceeding in which the director or officer has
been adjudged liable for having improperly received a personal benefit in his or her capacity as a director. </FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;A
director's conduct with respect to an employee benefit plan, for a purpose the director reasonably believed to be in the interests of the participants in and beneficiaries of the plan,
is conduct which complies with the indemnification standard set forth in the Articles. </FONT></P>


<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;An
indemnification determination may be made by the Company's Board of Directors by majority vote of a quorum consisting of directors not at the time parties to the proceeding, or, if
such a quorum cannot be obtained, by majority vote of a committee duly designated by the Board of Directors (in which deliberations the interested directors may participate) consisting solely of two
or more directors not at the time parties to the proceeding, or by a determination by special legal counsel engaged by the Board of Directors. Shareholders, by majority vote (excluding shares owned by
or voted under the control of directors who are at the time parties to the proceeding) may also order indemnification, as well as a court, upon application by the director or officer seeking
indemnification, if the court determines that the director or officer is fairly and reasonably entitled to indemnification in view of all of the relevant circumstances (whether or not that person met
the other standards set forth in the Articles). The Articles state that it is intended that indemnification be granted to the full extent permissible under the law, except for matters as to which
indemnification would be in contravention of the laws of the State of Indiana or the United States of America, whether as a matter of public policy or pursuant to any statutory provision. The
underlying statutory standard for director liability in Indiana is broad, providing that a director is not liable for any action taken as a director, or any failure to take any action, unless the
director has breached or failed to perform the duties of the director's office, and the breach or failure to perform constitutes willful misconduct or recklessness. </FONT></P>


<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The
Company maintains officers' and directors' liability insurance which insures, subject to policy limits and retention amounts, against liabilities that officers and directors of the
Company may incur in their respective capacities. </FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;We
refer you to Item 9(c) regarding our undertakings with respect to indemnification for liabilities arising under the Securities Act. </FONT></P>

<P><FONT SIZE=2><B>ITEM 7.&nbsp;&nbsp;&nbsp;&nbsp;Exemption from Registration Claimed.  </B></FONT></P>


<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Not Applicable. </FONT></P>

<P><FONT SIZE=2><B>ITEM 8.&nbsp;&nbsp;&nbsp;&nbsp;Exhibits.  </B></FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;See Index to Exhibits on page 7 of this Registration Statement. </FONT></P>

<P><FONT SIZE=2><B>ITEM 9.&nbsp;&nbsp;&nbsp;&nbsp;Undertakings.  </B></FONT></P>

<DL compact>
<DT style='margin-bottom:-11pt;'><FONT SIZE=2>(a)</FONT></DT><DD><FONT SIZE=2>The
undersigned Registrant hereby undertakes:
<BR><BR></FONT>
<DL compact>
<DT style='margin-bottom:-11pt;'><FONT SIZE=2>(1)</FONT></DT><DD><FONT SIZE=2>to
file, during any period in which offers or sales are being made, a post-effective amendment to this Registration Statement:
<BR><BR></FONT>
<DL compact>
<DT style='margin-bottom:-11pt;'><FONT SIZE=2>(i)</FONT></DT><DD><FONT SIZE=2>to
include any prospectus required by Section&nbsp;10(a)(3) of the Securities Act of 1933;
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(ii)</FONT></DT><DD><FONT SIZE=2>to
reflect in the prospectus any facts or events arising after the effective date of the Registration Statement (or the most recent post-effective amendment
thereof) which, </FONT></DD></DL>
</DD></DL>
</DD></DL>
<P ALIGN="CENTER"><FONT SIZE=2>3</FONT></P>

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<UL>
<UL>

<P><FONT SIZE=2>individually
or in the aggregate, represent a fundamental change in the information set forth in the Registration Statement. Notwithstanding the foregoing, any increase or decrease in volume of
securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may
be reflected in the form of prospectus filed with the SEC pursuant to Rule&nbsp;424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum
aggregate offering price set forth in the "Calculation of Registration Fee" table in the effective Registration Statement; </FONT></P>

</UL>
<DL compact>
<DT style='margin-bottom:-11pt;'><FONT SIZE=2>(iii)</FONT></DT><DD><FONT SIZE=2>to
include any material information with respect to the plan of distribution not previously disclosed in the Registration Statement or any material change to such
information in the Registration Statement; provided, however,
<BR><BR></FONT>
<DL compact>
<DT style='margin-bottom:-11pt;'><FONT SIZE=2>(A)</FONT></DT><DD><FONT SIZE=2>that
Paragraphs (a)(1)(i)&nbsp;and (a)(1)(ii)&nbsp;of this section do not apply if the registration statement is on Form&nbsp;S-8, and the information required to be
included in a post-effective amendment by those clauses is contained in reports filed with or furnished to the Commission by the Registrant pursuant to Section&nbsp;13 or
Section&nbsp;15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the Registration Statement;
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(B)</FONT></DT><DD><FONT SIZE=2>that
for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement
relating to the securities to be offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof;
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(C)</FONT></DT><DD><FONT SIZE=2>to
remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering;
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(D)</FONT></DT><DD><FONT SIZE=2>that
for the purpose of determining liability of the Registrant under the Securities Act to any purchaser in the initial distribution of the securities, the undersigned Registrant
undertakes that in a primary offering of securities of the undersigned Registrant pursuant to this Registration Statement, regardless of the underwriting method used to sell the securities to the
purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned Registrant will be a seller to the purchaser and will be considered
to offer or sell such securities to such purchaser:
<BR><BR></FONT>
<DL compact>
<DT style='margin-bottom:-11pt;'><FONT SIZE=2>(i)</FONT></DT><DD><FONT SIZE=2>Any
preliminary prospectus or prospectus of the undersigned Registrant relating to the offering required to be filed pursuant to Rule&nbsp;424;
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(ii)</FONT></DT><DD><FONT SIZE=2>Any
free writing prospectus relating to the offering prepared by or on behalf of the undersigned Registrant or used or referred to by the undersigned Registrant;
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(iii)</FONT></DT><DD><FONT SIZE=2>The
portion of any other free writing prospectus relating to the offering containing material information about the undersigned Registrant or its securities provided
by or on behalf of the undersigned Registrant; and
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(iv)</FONT></DT><DD><FONT SIZE=2>Any
other communication that is an offer in the offering made by the undersigned Registrant to the purchaser </FONT></DD></DL>
</DD></DL>
</DD></DL>
</UL>
</UL>
<P ALIGN="CENTER"><FONT SIZE=2>4</FONT></P>

<HR NOSHADE>
<P style='page-break-before:always'></p>
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<DL compact>
<DT style='margin-bottom:-11pt;'><FONT SIZE=2>(b)</FONT></DT><DD><FONT SIZE=2>The
undersigned Registrant hereby undertakes that, for purposes of determining any liabilities under the Securities Act, each filing of any of Registrant's annual reports pursuant to
Section&nbsp;13(a) or Section&nbsp;15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section&nbsp;15(d) of the Exchange Act)
that is incorporated by reference in the Registration Statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at
that time shall be deemed to be the initial bona fide offering thereof.
<BR><BR></FONT></DD><DT style='margin-bottom:-11pt;'><FONT SIZE=2>(c)</FONT></DT><DD><FONT SIZE=2>Insofar
as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers or controlling persons of Registrant pursuant to the provisions
described in Item 6 herein, or otherwise, Registrant has been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act and is, therefore,
unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by a director, officer or controlling
person in a successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the Registrant will,
unless in the opinion of its counsel the question has already been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is
against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue. </FONT></DD></DL>
<P ALIGN="CENTER"><FONT SIZE=2>5</FONT></P>

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<BR></FONT><FONT SIZE=2><B>SIGNATURES    <BR>    </B></FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form&nbsp;S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the city of Fort
Wayne, Indiana, on November&nbsp;6, 2007. </FONT></P>

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<TD WIDTH="39%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD COLSPAN=2><FONT SIZE=2>STEEL DYNAMICS,&nbsp;INC.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD WIDTH="39%"><FONT SIZE=2><BR>
&nbsp;</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="4%"><FONT SIZE=2><BR>
By:</FONT></TD>
<TD WIDTH="54%"><FONT SIZE=2><BR>
/s/&nbsp;&nbsp;</FONT><FONT SIZE=2>Theresa E. Wagler&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><HR NOSHADE><FONT SIZE=2> Theresa E. Wagler<BR>
Vice President and Chief Financial Officer</FONT></TD>
</TR>
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<P ALIGN="CENTER"><FONT SIZE=2><A
NAME="ja46501_power_of_attorney"> </A>
<A NAME="toc_ja46501_2"> </A>
<BR></FONT><FONT SIZE=2><B>POWER OF ATTORNEY    <BR>    </B></FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;KNOW ALL PERSONS BY THESE PRESENTS that each person whose signature appears below constitutes and appoints Theresa E. Wagler, Mark D. Millett or Richard P. Teets,
Jr., or any of them, as his true and lawful attorney-in-fact with full power of substitution and resubstitution, in any and all capacities, to sign this Registration Statement
or any amendments thereto (including post-effective amendments) and to file the same with all exhibits thereto, as well as other documents in connection therewith, with the Securities and
Exchange Commission, granting unto each of such attorneys-in-fact and agents full power and authority to do and perform each and every act and thing requisite and necessary to
be done in and about the matters set forth herein, as fully to all intents and purposes as he might or could do in
person, hereby ratifying and confirming all that said attorney-in-fact and agent, or his or her substitutes, may lawfully do or cause to be done by virtue hereof. </FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pursuant
to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed on November&nbsp;6, 2007, by the following persons in the capacities
indicated: </FONT></P>

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<TD WIDTH="40%"><FONT SIZE=2><BR>
/s/&nbsp;&nbsp;</FONT><FONT SIZE=2>Keith E. Busse&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><HR NOSHADE><FONT SIZE=2> Keith E. Busse</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="58%"><FONT SIZE=2><BR>
Chairman, Chief Executive Officer and Director<BR>
(principal executive officer)</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="40%" VALIGN="TOP"><FONT SIZE=2><BR>
/s/&nbsp;&nbsp;</FONT><FONT SIZE=2>Mark D. Millett&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><HR NOSHADE><FONT SIZE=2> Mark D. Millett</FONT></TD>
<TD WIDTH="3%" VALIGN="TOP"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="58%" VALIGN="TOP"><FONT SIZE=2><BR>
Executive Vice President and Director</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="40%" VALIGN="TOP"><FONT SIZE=2><BR>
/s/&nbsp;&nbsp;</FONT><FONT SIZE=2>Richard P. Teets, Jr.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><HR NOSHADE><FONT SIZE=2> Richard P. Teets, Jr.</FONT></TD>
<TD WIDTH="3%" VALIGN="TOP"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="58%" VALIGN="TOP"><FONT SIZE=2><BR>
Executive Vice President and Director</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="40%" VALIGN="TOP"><FONT SIZE=2><BR>
/s/&nbsp;&nbsp;</FONT><FONT SIZE=2>Daniel M. Rifkin&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><HR NOSHADE><FONT SIZE=2> Daniel M. Rifkin</FONT></TD>
<TD WIDTH="3%" VALIGN="TOP"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="58%" VALIGN="TOP"><FONT SIZE=2><BR>
Executive Vice President and Director</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="40%" VALIGN="TOP"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="3%" VALIGN="TOP"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="58%" VALIGN="TOP"><FONT SIZE=2>&nbsp;</FONT></TD>
</TR>
</TABLE>
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<P ALIGN="CENTER"><FONT SIZE=2>6</FONT></P>

<HR NOSHADE>
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/s/&nbsp;&nbsp;</FONT><FONT SIZE=2>Theresa E. Wagler&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><HR NOSHADE><FONT SIZE=2> Theresa E. Wagler</FONT></TD>
<TD WIDTH="3%" VALIGN="TOP"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="58%" VALIGN="TOP"><FONT SIZE=2><BR>
Vice President and Chief Financial Officer</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="40%" VALIGN="TOP"><FONT SIZE=2><BR>
/s/&nbsp;&nbsp;</FONT><FONT SIZE=2>John C. Bates&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><HR NOSHADE><FONT SIZE=2> John C. Bates</FONT></TD>
<TD WIDTH="3%" VALIGN="TOP"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="58%" VALIGN="TOP"><FONT SIZE=2><BR>
Director</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="40%" VALIGN="TOP"><FONT SIZE=2><BR>
/s/&nbsp;&nbsp;</FONT><FONT SIZE=2>Frank D. Byrne, M.D.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><HR NOSHADE><FONT SIZE=2> Frank D. Byrne, M.D.</FONT></TD>
<TD WIDTH="3%" VALIGN="TOP"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="58%" VALIGN="TOP"><FONT SIZE=2><BR>
Director</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="40%" VALIGN="TOP"><BR><HR NOSHADE><FONT SIZE=2> Paul B. Edgerley</FONT></TD>
<TD WIDTH="3%" VALIGN="TOP"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="58%" VALIGN="TOP"><FONT SIZE=2><BR>
Director</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="40%" VALIGN="TOP"><FONT SIZE=2><BR>
/s/&nbsp;&nbsp;</FONT><FONT SIZE=2>Richard J. Freeland&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><HR NOSHADE><FONT SIZE=2> Richard J. Freeland</FONT></TD>
<TD WIDTH="3%" VALIGN="TOP"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="58%" VALIGN="TOP"><FONT SIZE=2><BR>
Director</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="40%" VALIGN="TOP"><BR><HR NOSHADE><FONT SIZE=2> Dr. J&uuml;rgen Kolb</FONT></TD>
<TD WIDTH="3%" VALIGN="TOP"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="58%" VALIGN="TOP"><FONT SIZE=2><BR>
Director</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="40%" VALIGN="TOP"><BR><HR NOSHADE><FONT SIZE=2> James C. Marcuccilli</FONT></TD>
<TD WIDTH="3%" VALIGN="TOP"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="58%" VALIGN="TOP"><FONT SIZE=2><BR>
Director</FONT></TD>
</TR>
<TR VALIGN="BOTTOM">
<TD WIDTH="40%" VALIGN="TOP"><FONT SIZE=2><BR>
/s/&nbsp;&nbsp;</FONT><FONT SIZE=2>Joseph D. Ruffolo&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT><HR NOSHADE><FONT SIZE=2> Joseph D. Ruffolo</FONT></TD>
<TD WIDTH="3%" VALIGN="TOP"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="58%" VALIGN="TOP"><FONT SIZE=2><BR>
Director</FONT></TD>
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<P ALIGN="CENTER"><FONT SIZE=2>7</FONT></P>

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<BR></FONT><FONT SIZE=2><B>INDEX TO EXHIBITS    <BR>    </B></FONT></P>

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<TH WIDTH="10%" ALIGN="CENTER"><FONT SIZE=1><B>Exhibit<BR>
Number</B></FONT><HR NOSHADE></TH>
<TH WIDTH="3%"><FONT SIZE=1>&nbsp;</FONT></TH>
<TH WIDTH="88%" ALIGN="CENTER"><FONT SIZE=1><B>Description of Document</B></FONT><HR NOSHADE></TH>
</TR>
<TR VALIGN="TOP">
<TD WIDTH="10%" ALIGN="RIGHT"><BR><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="88%"><FONT SIZE=2><BR>
&nbsp;</FONT></TD>
</TR>
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<TD WIDTH="10%" ALIGN="RIGHT"><FONT SIZE=2>3.1</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="88%"><FONT SIZE=2>Amended Articles of Incorporation of Steel Dynamics, Inc., incorporated by reference from Item 5.01 and the exhibit thereto, to our Form 8-K, filed March 18, 2005</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD WIDTH="10%" ALIGN="RIGHT"><FONT SIZE=2><BR>
3.2</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="88%"><FONT SIZE=2><BR>
Amended Bylaws of Steel Dynamics, Inc., incorporated herein by reference from Exhibit 3.1 to our Report on Form 8-K, Item 5.03, filed July 6, 2006</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD WIDTH="10%" ALIGN="RIGHT"><FONT SIZE=2><BR>
4.0</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="88%"><FONT SIZE=2><BR>
Specimen stock certificate (incorporated by reference to Exhibit 4.1 to our Registration Statement on Form 8-A, SEC File No. 96661016, filed November 13, 1996)</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD WIDTH="10%" ALIGN="RIGHT"><FONT SIZE=2><BR>
5.1</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="88%"><FONT SIZE=2><BR>
Opinion of Barrett &amp; McNagny LLP as to the legality of the shares of Common Stock</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD WIDTH="10%" ALIGN="RIGHT"><FONT SIZE=2><BR>
10.19</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="88%"><FONT SIZE=2><BR>
Amended and Restated 1996 Incentive Stock Option Plan, incorporated by reference from Exhibit 10.19 to our 2001 Annual Report on Form 10-K, filed March 28, 2002.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD WIDTH="10%" ALIGN="RIGHT"><FONT SIZE=2><BR>
10.40</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="88%"><FONT SIZE=2><BR>
Non-Employee Director Stock Option Plan, incorporated by reference from Exhibit 10.40 to our June 30, 2000 Form 10-Q, filed August 11, 2000.</FONT></TD>
</TR>
<TR VALIGN="TOP">
<TD WIDTH="10%" ALIGN="RIGHT"><FONT SIZE=2><BR>
10.41</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="88%"><FONT SIZE=2><BR>
2006 Equity Incentive Plan, incorporated by reference from Exhibit 10.41 to our Annual Report on Form 10-K, filed February 26, 2007.</FONT></TD>
</TR>
<TR VALIGN="TOP">
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23.1</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="88%"><FONT SIZE=2><BR>
Consent of Ernst &amp; Young LLP</FONT></TD>
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<TD WIDTH="10%" ALIGN="RIGHT"><FONT SIZE=2><BR>
23.2</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="88%"><FONT SIZE=2><BR>
Consent of Barrett &amp; McNagny LLP (included in Exhibit 5.1)</FONT></TD>
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24.1</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="88%"><FONT SIZE=2><BR>
Power of Attorney (included on page 6)</FONT></TD>
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<P ALIGN="CENTER"><FONT SIZE=2>8</FONT></P>

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<BR>
<P><br><A NAME="07ZDO46501_1">QuickLinks</A><br></P><!-- TOC_BEGIN -->
<FONT SIZE=2><A HREF="#toc_bc46501_1">PART I Information Required in the Section 10(a) Prospectus</A></FONT><BR>
<!-- TOC_BEGIN -->
<FONT SIZE=2><A HREF="#toc_de46501_1">PART II Information Required in the Registration Statement</A></FONT><BR>
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<FONT SIZE=2><A HREF="#toc_ja46501_1">SIGNATURES</A></FONT><BR>
<FONT SIZE=2><A HREF="#toc_ja46501_2">POWER OF ATTORNEY</A></FONT><BR>
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<FONT SIZE=2><A HREF="#toc_jc46501_1">INDEX TO EXHIBITS</A></FONT><BR>
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<TYPE>EX-5.1
<SEQUENCE>2
<FILENAME>a2180886zex-5_1.htm
<DESCRIPTION>EXHIBIT 5.1
<TEXT>
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NAME="ma46501_exhibit_5.1"> </A>
<A NAME="toc_ma46501_1"> </A>
<BR></FONT><FONT SIZE=2><B>Exhibit&nbsp;5.1    <BR>    </B></FONT></P>

<P><FONT SIZE=2>Barrett&nbsp;&amp;
McNagny LLP<BR>
215 East Berry Street<BR>
Fort Wayne, IN 46802 </FONT></P>

<P><FONT SIZE=2>November
9, 2007 </FONT></P>

<P><FONT SIZE=2>Steel
Dynamics,&nbsp;Inc.<BR>
6714 Pointe Inverness Way, Suite 200<BR>
Fort Wayne, IN 46804 </FONT></P>

<P><FONT SIZE=2>Ladies
and Gentlemen: </FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;You
have requested our opinion with respect to certain matters in connection with the filing by Steel Dynamics,&nbsp;Inc., an Indiana corporation (the
"</FONT><FONT SIZE=2><B><I>Company</I></B></FONT><FONT SIZE=2>") of a Registration Statement on Form&nbsp;S-8 (the "</FONT><FONT SIZE=2><B><I>Registration Statement</I></B></FONT><FONT SIZE=2>")
with the Securities and Exchange Commission covering the offering of up to an aggregate of 8,320,881 shares of the Company's Common Stock, $0.001 par value (the </FONT> <FONT SIZE=2><B><I>"Shares"</I></B></FONT><FONT SIZE=2>), including
(i)&nbsp;6,720,971 shares reserved for issuance pursuant to the Company's 2006 Equity Incentive Plan (the </FONT> <FONT SIZE=2><B><I>"2006 Plan"</I></B></FONT><FONT SIZE=2>), (ii)&nbsp;730,353 shares reserved for issuance upon exercise of stock
options under the Company's 2006 Plan, (iii)&nbsp;751,817 shares
reserved for issuance upon exercise of stock options pursuant to the Company's Amended and Restated 1996 Incentive Stock Option Plan, (iv)&nbsp;24,829 shares issued as restricted stock to
non-employee directors pursuant to the 2006 Plan, (v)&nbsp;36,582 shares reserved for issuance upon exercise of stock options pursuant to the Company's Non-Employee Director
Stock Option Plan (the "</FONT><FONT SIZE=2><B><I>Director Plan</I></B></FONT><FONT SIZE=2>"), and (vi)&nbsp;56,330 shares issued as unrestricted stock awards pursuant to the 2006 Plan to certain
employees of an acquired subsidiary. </FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;In
connection with this opinion, we have examined the Registration Statement and related prospectus, the Company's Amended Articles of Incorporation and Bylaws, all of the foregoing
Plans, and such other documents, records, certificates, memoranda and other instruments as in our judgment are
necessary or appropriate to enable us to render the opinion expressed below. We have assumed the genuineness and authenticity of all documents submitted to us as originals, the conformity to originals
of all documents submitted to us as copies thereof, and the due execution and delivery of all documents where due execution and delivery are a prerequisite to the effectiveness thereof. Our opinion is
expressed only with respect to the Business Corporation Law of the State of Indiana. </FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;On
the basis of the foregoing, and in reliance thereon, we are of the opinion that the reserved shares, when issued in accordance with the 2006 Plan and the contemplated grants and
awards thereunder, as applicable, the reserved shares when issued in accordance with the 1996 Plan and the options issued thereunder, as applicable, and the director shares, when issued in accordance
with the Director Plan and the options issued thereunder, and in each case when sold and issued in accordance with the Registration Statement and related prospectus, will be validly issued, fully
paid, and nonassessable. </FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;We
consent to the filing of this Opinion as an exhibit to the Registration Statement. </FONT></P>

<P><FONT SIZE=2>Very
truly yours, </FONT></P>

<P><FONT SIZE=2>BARRETT&nbsp;&amp;
McNAGNY LLP </FONT></P>

<P><FONT SIZE=2>/s/
Robert S. Walters </FONT></P>

<P><FONT SIZE=2>Robert
S. Walters </FONT></P>

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<UL>
<FONT SIZE=2><A HREF="#toc_ma46501_1">Exhibit 5.1</A></FONT><BR>
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<DOCUMENT>
<TYPE>EX-23.1
<SEQUENCE>3
<FILENAME>a2180886zex-23_1.htm
<DESCRIPTION>EXHIBIT 23.1
<TEXT>
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NAME="mg46501_exhibit_23.1"> </A>
<A NAME="toc_mg46501_1"> </A>
<BR></FONT><FONT SIZE=2><B>Exhibit&nbsp;23.1    <BR>    </B></FONT></P>

<P ALIGN="CENTER"><FONT SIZE=2><A
NAME="mg46501_consent_of_independent__mg402320"> </A>
<A NAME="toc_mg46501_2"> </A>
<BR></FONT><FONT SIZE=2><B>CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM    <BR>    </B></FONT></P>

<P><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;We consent to the incorporation by reference in the Registration Statement on Form&nbsp;S-8 to be filed on November&nbsp;&nbsp;&nbsp;&nbsp;, 2007 pertaining
to the Steel Dynamics,&nbsp;Inc. 2006 Equity Incentive Plan, the Steel Dynamics,&nbsp;Inc. Amended and Restated 1996 Incentive Stock Plan, and the Steel Dynamics,&nbsp;Inc.
Non-Employee Director Stock Option Plan, of our reports dated February&nbsp;20, 2007, with respect to the consolidated financial statements of Steel Dynamics,&nbsp;Inc., included in
its Annual Report (Form&nbsp;10-K) for the year ended December&nbsp;31, 2006, Steel Dynamics,&nbsp;Inc. management's assessment of internal control over financial reporting, and the
effectiveness of internal control over financial reporting of Steel Dynamics,&nbsp;Inc., filed with the Securities and Exchange Commission on February&nbsp;26, 2007. </FONT></P>

<P><FONT SIZE=2>/s/
Ernst&nbsp;&amp; Young LLP<BR>
Fort Wayne, Indiana </FONT></P>

<P><FONT SIZE=2>November
7, 2007 </FONT></P>

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<UL>
<FONT SIZE=2><A HREF="#toc_mg46501_1">Exhibit 23.1</A></FONT><BR>
</UL>
<FONT SIZE=2><A HREF="#toc_mg46501_2">CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM</A></FONT><BR>

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