STEEL DYNAMICS INC — Director's Dealing 2010

May 20, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: STEEL DYNAMICS INC (STLD)
CIK: 0001022671
Period of Report: 2010-05-18

Reporting Person: MILLETT MARK D (Director, Executive Vice President)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-05-18	Common Stock	M	8576	$7.00	Acquired	2798593	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-05-18	Employee Stock Option (right to buy)	$7.00	M	8576	Disposed	2010-05-21	Common Stock (8576)	Direct

Footnotes

F1: Acquisition of stock pursuant to exercise of employee stock option, exempt from Section 16(b) under Rule 16b-3(d) and Rule 16b-6.

F2: Disposition to issuer of option, exempt from Section 16(b) under Rule 16b-3(e).