Attached files

file filename
10-K/A - 10-K/A - STEEL DYNAMICS INCa2197103z10-ka.htm
EX-32.1 - EXHIBIT 32.1 - STEEL DYNAMICS INCa2196582zex-32_1.htm
EX-32.2 - EXHIBIT 32.2 - STEEL DYNAMICS INCa2196582zex-32_2.htm
EX-12.1 - EXHIBIT 12.1 - STEEL DYNAMICS INCa2196582zex-12_1.htm
EX-31.2 - EXHIBIT 31.2 - STEEL DYNAMICS INCa2196582zex-31_2.htm
EX-23.1 - EXHIBIT 23.1 - STEEL DYNAMICS INCa2196582zex-23_1.htm
EX-31.1 - EXHIBIT 31.1 - STEEL DYNAMICS INCa2196582zex-31_1.htm
EX-10.19 - EXHIBIT 10.19 - STEEL DYNAMICS INCa2196582zex-10_19.htm
EX-10.40 - EXHIBIT 10.40 - STEEL DYNAMICS INCa2196582zex-10_40.htm

QuickLinks -- Click here to rapidly navigate through this document


EXHIBIT 21.1

Name
  Percent of Capital
Stock/Equity Units
Owned by
Steel Dynamics, Inc.
  Percent of Voting
Stock/Voting Units
Owned by
Steel Dynamics, Inc.
 

Dynamic Aviation, LLC (Indiana)

    100 %   100 %

New Millennium Building Systems, LLC (Indiana)

    100 %   100 %

OmniSource Corporation (Indiana)

    100 %   100 %

Paragon Steel Enterprises, LLC (Indiana)

    50 %   50 %

Roanoke Electric Steel Corporation (Indiana)

    100 %   100 %

SDI Investment Company (Delaware)

    100 %   100 %

Shredded Products II, LLC (Virginia)

    100 %   100 %

Steel Dynamics Sales North America, Inc. (Indiana)

    100 %   100 %

STLD Holdings, Inc. (Indiana)

    100 %   100 %

The Techs Industries, Inc. (Pennsylvania)

    100 %   100 %



QuickLinks