Document:

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                                                                    EXHIBIT 4.4C

                          THIRD SUPPLEMENTAL INDENTURE

      THIS THIRD SUPPLEMENTAL INDENTURE is dated as of December 31, 2002, among
STEEL DYNAMICS, INC., an Indiana corporation (the "Company"), SDI INVESTMENT
COMPANY, a Delaware corporation, (the "Initial Subsidiary Guarantor"), DYNAMIC
BAR PRODUCTS, LLC, an Indiana limited liability company (the "Second Subsidiary
Guarantor"), STLD HOLDINGS, INC. an Indiana corporation, FERROUS RESOURCES, LLC,
an Indiana limited liability company (STLD Holdings, Inc. and Ferrous Resources,
LLC may individually be referred to as the "Additional Subsidiary Guarantor" and
collectively as the "Additional Subsidiary Guarantors"), STEEL DYNAMICS SALES
NORTH AMERICA, INC., an Indiana corporation (the "New Subsidiary Guarantor"),
and FIFTH THIRD BANK, INDIANA, a state banking association, as trustee (the
"Trustee").

                                    RECITALS:

      The Company, the Initial Subsidiary Guarantor and the Trustee have duly
authorized, executed and delivered an Indenture dated as of March 26, 2002 (the
"Original Indenture") in connection with the issuance initially of up to
$200,000,000 aggregate principal amount of the Company's 9-1/2% Senior Notes due
2009 (the "Notes") as provided in the Original Indenture.

      The Company, the Initial Subsidiary Guarantor, the Second Subsidiary
Guarantor, and the Trustee entered into a First Supplemental Indenture dated as
of September 6, 2002.

      The Company, the Initial Subsidiary Guarantor, the Second Subsidiary
Guarantor, the Additional Subsidiary Guarantors and the Trustee entered into a
Second Supplemental Indenture dated as of September 30, 2002.

      This Third Supplemental Indenture is being executed and delivered by the
Company, the Initial Subsidiary Guarantor, the Second Subsidiary Guarantor, the
Additional Subsidiary Guarantors and the New Subsidiary Guarantor pursuant to
the provisions of Section 4.20 and Section 9.01(2) of the Original Indenture.

      This Third Supplemental Indenture (together with the Original Indenture,
the First Supplemental Indenture and the Second Supplemental Indenture,
collectively the "Indenture") is subject to, and shall be governed by, the
provisions of the Trust Indenture Act of 1939, as amended, that are required to
be a part of and to govern indentures qualified under the Trust Indenture Act of
1939, as amended.

            AND THIS THIRD SUPPLEMENTAL INDENTURE FURTHER WITNESSETH:

      For and in consideration of the premises, it is mutually covenanted and
agreed, for the equal and proportionate benefit of all Holders, as follows:
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                                  ARTICLE ONE

                               Guaranty of Notes

      Section 1.01. Note Guarantee; Limitation of Liability. (a) Subject to the
provisions of Article Ten of the Original Indenture, the New Subsidiary
Guarantor hereby, jointly and severally with the Initial Subsidiary Guarantor,
the Second Subsidiary Guarantor and the Additional Subsidiary Guarantors, fully
and unconditionally guarantee to each Holder of Notes and to the Trustee on
behalf of the Holders: (i) the due and punctual payment of the principal of,
premium, if any, on and interest on each Note, when and as the same shall become
due and payable, whether at maturity, by acceleration or otherwise, the due and
punctual payment of interest on the overdue principal of and interest, if any,
on the Notes, to the extent lawful, and the due and punctual performance of all
other obligations of the Company to the Holders or the Trustee, all in
accordance with the terms of such Note, the Original Indenture, the First
Supplemental Indenture, the Second Supplemental Indenture and this Third
Supplemental Indenture and (ii) in the case of any extension of time of payment
or renewal of any Notes or any of such other obligations, that the same will be
promptly paid in full when due or performed in accordance with the terms of the
extension or renewal, at Stated Maturity, by acceleration or otherwise, subject,
however, in the case of clauses (i) and (ii) above, to the limitations set forth
in the second paragraph of Section 10.01 of the Original Indenture.

      (b)   The undersigned, and by their acceptance of this Third Supplemental
Indenture, hereby confirm that it is the intention of all such Persons that this
Third Supplemental Indenture, the Original Indenture, the First Supplemental
Indenture and the Second Supplemental Indenture and the obligations of the
undersigned hereunder and thereunder not constitute a fraudulent transfer or
conveyance for purposes of Bankruptcy Law, the Uniform Fraudulent Conveyance
Act, the Uniform Fraudulent Transfer Act or any similar foreign, federal or
state law to the extent applicable to this Third Supplemental Indenture, the
Original Indenture, the First Supplemental Indenture, the Second Supplemental
Indenture and the obligations of the undersigned hereunder and thereunder. To
effectuate the foregoing intention, the undersigned hereby irrevocably agree
that the obligations of the undersigned under this Third Supplemental Indenture,
the Original Indenture, the First Supplemental Indenture and the Second
Supplemental Indenture at any time shall be limited to the maximum amount as
will result in the obligations of the undersigned under this Third Supplemental
Indenture, the Original Indenture, the First Supplemental Indenture and the
Second Supplemental Indenture not constituting a fraudulent transfer or
conveyance.

      Section 1.02. Obligations under the Original Indenture. The New Subsidiary
Guarantor hereby agrees, as of the date first above written, to be bound as a
Subsidiary Guarantor by all of the terms and conditions of the Original
Indenture to the same extent as each of the other Subsidiary Guarantors
thereunder. The New Subsidiary Guarantor further agrees, as of the date first
above written, that each reference in the Original Indenture to a "SUBSIDIARY
GUARANTOR" shall also mean and be a reference to the New Subsidiary Guarantor,
and each reference in any of the Notes to a "SUBSIDIARY GUARANTOR" shall also
mean and be a reference to the New Subsidiary Guarantor.

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      Section 1.03. Covenants and Agreements. The New Subsidiary Guarantor makes
each covenant and agreement set forth in Article Ten of the Original Indenture
to the same extent as each other Subsidiary Guarantor.

                                  ARTICLE TWO

                                 Miscellaneous

      Section 2.01. Remainder of Original Indenture Unaffected. Except as
specifically provided in Article One above, the terms of the Original Indenture
shall remain unchanged and in full force and effect, and shall govern the
interpretation and application of this Third Supplemental Indenture.

      Section 2.02. Duplicate Originals; Delivery by Telecopier. The parties may
sign any number of copies of this Third Supplemental Indenture. Each signed copy
shall be an original, but all of them together represent the same agreement.
Delivery of an executed counterpart of a signature page to this Third
Supplemental Indenture by telecopier shall be effective as delivery of an
original executed counterpart of this Third Supplemental Indenture.

      Section 2.03. Separability. In case any provision in this Third
Supplemental Indenture shall be invalid, illegal or unenforceable, the validity,
legality and enforceability of the remaining provisions shall not in any way be
affected or impaired thereby.

                              [End of Article Two]

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                                   SIGNATURES

      IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be
duly executed, all as of the date first written above.

"Company"                               STEEL DYNAMICS, INC.

                                        By:  ___________________________________
                                        Its  ___________________________________

"Initial Subsidiary Guarantor"          SDI INVESTMENT COMPANY

                                        By:  ___________________________________
                                        Its  ___________________________________

"Second Subsidiary Guarantor"           DYNAMIC BAR PRODUCTS, LLC

                                        By:  ___________________________________
                                        Its  ___________________________________

"Additional Subsidiary Guarantor"       STLD HOLDINGS, INC.

                                        By:  ___________________________________
                                        Its  ___________________________________

"Additional Subsidiary Guarantor"       FERROUS RESOURCES, LLC

                                        By:  ___________________________________
                                        Its  ___________________________________

"Trustee"                               FIFTH THIRD BANK, INDIANA

                                        By:  ___________________________________
                                        Its  ___________________________________

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"New Subsidiary Guarantor"              STEEL DYNAMICS SALES NORTH AMERICA, INC.

                                        By:  ___________________________________
                                        Its  ___________________________________

                                       5<PAGE>
                                                                   EXHIBIT 10.1B

                      SECOND AMENDMENT TO CREDIT AGREEMENT

            THIS SECOND AMENDMENT TO CREDIT AGREEMENT, dated as of December 16,
2002 (this "Amendment"), is among STEEL DYNAMICS, INC. (the "Borrower"), the
Lenders (as defined below) signatories hereto, JPMORGAN CHASE BANK, as
administrative agent for the Lenders (in such capacity, the "Administrative
Agent"), GENERAL ELECTRIC CAPITAL CORPORATION, as Documentation Agent, and
MORGAN STANLEY SENIOR FUNDING, INC., as Arranger and Syndication Agent.

                              W I T N E S S E T H:

            WHEREAS, the Borrower, certain financial institutions and other
Persons (such capitalized term and other capitalized terms used in these
recitals to have the meanings set forth or defined by reference in Part I below)
from time to time parties thereto (collectively, the "Lenders"), JPMorgan Chase
Bank, as Collateral Agent, the Administrative Agent, General Electric Capital
Corporation, as Documentation Agent, and Morgan Stanley Senior Funding, Inc., as
Arranger and Syndication Agent, are parties to the Credit Agreement, dated as of
March 26, 2002, as amended by the First Amendment to Credit Agreement, dated as
of August 6, 2002, and as waived by Letter Waiver, dated as of October 6, 2002
(such Credit Agreement, as so amended and waived, the "Existing Credit
Agreement");

            WHEREAS, the Borrower has requested that the Lenders amend the
Existing Credit Agreement as set forth below; and

            WHEREAS, the Lenders have agreed, subject to the terms and
conditions hereinafter set forth, to amend the Existing Credit Agreement in
certain respects as set forth below (the Existing Credit Agreement, as so
amended or otherwise modified by this Amendment, being referred to as the
"Credit Agreement");

            NOW, THEREFORE, in consideration of the premises and for other good
and valuable consideration (the receipt and sufficiency of which is hereby
acknowledged), the parties hereto hereby agree as follows:

                                     PART I
                                  DEFINITIONS

            SUBPART 1.1. Certain Definitions. The following terms (whether or
not underscored) when used in this Amendment shall have the following meanings
(such meanings to be equally applicable to the singular and plural forms
thereof):

            "Administrative Agent" is defined in the preamble.

            "Amendment" is defined in the preamble.

            "Borrower" is defined in the preamble.

            "Credit Agreement" is defined in the third recital.
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            "Existing Credit Agreement" is defined in the first recital.

            "Second Amendment Effective Date" is defined in Subpart 3.1.

            "Lenders" is defined in the first recital.

            SUBPART 1.2. Other Definitions. Terms for which meanings are
provided in the Existing Credit Agreement are, unless otherwise defined herein
or the context otherwise requires, used in this Amendment with such meanings.

                                    PART II
                                   AMENDMENTS

            Effective on (and subject to the occurrence of) the Second Amendment
Effective Date, the Existing Credit Agreement is hereby amended in accordance
with this Part; except as so amended or otherwise modified by this Amendment,
the Existing Credit Agreement and the Loan Documents shall continue in full
force and effect in accordance with their terms.

            SUBPART 2.1. Amendment to Article I. Article I of the Existing
Credit Agreement is hereby amended in accordance with Subpart 2.1.1.

                  SUBPART 2.1.1. Section 1.01 of the Existing Credit Agreement
      is hereby amended by inserting the following new definitions therein in
      the appropriate alphabetical order:

                  "Second Amendment" means the Second Amendment, dated as of
            December 16, 2002, to this Agreement among the Borrower, the
            Administrative Agent, Morgan Stanley Senior Funding, Inc. and the
            Lenders parties thereto.

                  "Second Amendment Effective Date" is defined in Subpart 3.1 of
            the Second Amendment.

            SUBPART 2.2. Amendment to Article V. Article V of the Existing
Credit Agreement is hereby amended in accordance with Subpart 2.2.1.

                  SUBPART 2.2.1. Section 5.02(b)(i) of the Existing Credit
      Agreement is hereby amended by adding at the end thereof new clauses (E)
      and (F) to read as follows:

                  "(E)  up to an additional $100,000,000 principal amount of
            Senior Notes at any time outstanding; and

                  (F)   up to $150,000,000 principal amount of unsecured
            convertible notes (convertible into common stock of the Borrower)
            with a maturity and redemption for all of such principal amount at
            least six months after the final maturity date of the Term B
            Advances (with the Borrower hereby agreeing not to prepay, redeem,
            repurchase or otherwise acquire any of such notes prior to the day
            which is six months after the final maturity date of the Term B
            Advances) with covenants and defaults no more restrictive on the
            Borrower than those

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<PAGE>
            contained in the Senior Notes, and if issued as subordinated debt,
            with subordination provisions reasonably satisfactory to the
            Arranger and the Administrative Agent."

                                    PART III
                          CONDITIONS TO EFFECTIVENESS

            SUBPART 3.1. Effectiveness. This Amendment and the amendments
contained herein shall become effective on the date (the "Second Amendment
Effective Date") when each of the conditions set forth in this Part shall have
been fulfilled to the satisfaction of the Administrative Agent.

                        SUBPART 3.1.1. Execution of Counterparts. The
      Administrative Agent and the Arranger shall have received counterparts of
      this Amendment, duly executed and delivered on behalf of the Borrower, the
      Administrative Agent and the Required Lenders.

                        SUBPART 3.1.2. Expenses. The Borrower shall have paid
      all expenses (including the fees and expenses of Shearman & Sterling)
      incurred in connection with the preparation, negotiation and execution of
      this Amendment and matters relating to the Credit Agreement from and after
      the closing thereof to the extent invoiced.

                        SUBPART 3.1.3. Legal Details, etc. All documents
      executed or submitted pursuant hereto shall be satisfactory in form and
      substance to the Administrative Agent and the Arranger and Shearman &
      Sterling as counsel. The Administrative Agent, the Arranger and counsel
      shall have received all information and such counterpart originals or such
      certified or other copies or such materials as the Administrative Agent,
      the Arranger or counsel may reasonably request, and all legal matters
      incident to the transactions contemplated by this Amendment shall be
      satisfactory to the Administrative Agent, the Arranger and counsel.

                                    PART IV
                  MISCELLANEOUS; REPRESENTATIONS AND COVENANTS

            SUBPART 4.1. Continuing Effectiveness, etc. As amended hereby, the
Credit Agreement shall remain in full force and effect and is hereby ratified
and confirmed in all respects. After the Second Amendment Effective Date, all
references in the Credit Agreement and each other Loan Document to the
"Agreement" or "Credit Agreement", as applicable, shall refer to the Existing
Credit Agreement, after giving effect to this Amendment, and this Amendment
shall be a Loan Document for all purposes. The Borrower hereby confirms its
obligations under Section 8.04 of the Credit Agreement to pay all fees and
expenses of the Administrative Agent and the Arranger (including reasonable fees
and out-of-pocket expenses of Shearman & Sterling) in connection with this
Amendment and other ongoing administration of the Credit Agreement as provided
in Section 8.04 of the Credit Agreement since the last invoice it received.

            SUBPART 4.2. Mandatory Prepayments. The Borrower hereby confirms its
obligations under Section 2.06(b)(iii) of the Credit Agreement to prepay an
aggregate principal amount of Advances equal to 75% of the amount of Net Cash
Proceeds from the incurrence or

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issuance by the Borrower of any Debt described in Sections 5.02(b)(i)(E) and (F)
of the Credit Agreement.

            SUBPART 4.3. Counterparts. This Amendment may be executed in any
number of counterparts and by the different parties on separate counterparts,
and each such counterpart shall be deemed to be an original but all such
counterparts shall together constitute one and the same Amendment.

            SUBPART 4.4. Governing Law. THIS AMENDMENT SHALL BE A CONTRACT MADE
UNDER AND GOVERNED BY THE INTERNAL LAWS OF THE STATE OF NEW YORK.

            SUBPART 4.5. Successors and Assigns. This Amendment shall be binding
upon the Borrower, the Lenders and the Agents and their respective successors
and assigns, and shall inure to their successors and assigns.

            SUBPART 4.6. Representations and Warranties. In order to induce the
Lenders to execute and deliver this Amendment, the Borrower represents and
warrants to the Agents, the Lenders and the Issuing Bank that, after giving
effect to the terms of this Amendment, the following statements are true and
correct: (a) the representations and warranties set forth in Article IV of the
Existing Credit Agreement and in the other Loan Documents are true and correct
on the Second Amendment Effective Date as if made on the Second Amendment
Effective Date and after giving effect to the Second Amendment (unless stated to
relate solely to an earlier date, in which case such representations and
warranties were true and correct in all material respects as of such earlier
date) and (b) no Default has occurred and is continuing.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK.]

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            IN WITNESS WHEREOF, the parties hereto have caused this Amendment to
be executed and delivered by their respective authorized officers as of the day
and year first above written.

                                      STEEL DYNAMICS, INC.

                                      By:  /s/ THERESA WAGLER
                                          -------------------------------------
                                          Title: ASSISTANT SECRETARY
LENDERS:

                                      JPMORGAN CHASE BANK,
                                        as Administrative Agent and Collateral
                                            Agent and as a Lender

                                      By: /s/ JAMES H. RAMAGE
                                          -------------------------------------
                                          Title: MANAGING DIRECTOR

                                      MORGAN STANLEY SENIOR FUNDING, INC.,
                                        as Arranger and Syndication Agent and as
                                            a Lender

                                      By: /s/ LUCY K. GALBRAITH
                                          ----------------------------------
                                          Title: VICE PRESIDENT

                                      GENERAL ELECTRIC CAPITAL CORPORATION,
                                        as Documentation Agent and as a Lender

                                      By:  /s/ ILLEGIBLE
                                          ----------------------------------
                                          Title: DULY AUTHORIZED SIGNATORY

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