STEEL DYNAMICS INC — Director's Dealing 2010

May 19, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: STEEL DYNAMICS INC (STLD)
CIK: 0001022671
Period of Report: 2010-05-17

Reporting Person: TEETS RICHARD P JR (Director, Executive Vice President)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-05-17	Common Stock	M	8576	$7.00	Acquired	4968417	Direct
2010-05-17	Common Stock	M	7688	$7.81	Acquired	4976105	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-05-17	Employee Stock Option (right to buy)	$7.00	M	8576	Disposed	2010-05-21	Common Stock (8576)	Direct
2010-05-17	Employee Stock Option (right to buy)	$7.81	M	7688	Disposed	2010-11-21	Common Stock (7688)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	5916	Indirect
Common Stock	5916	Indirect
Common Stock	84000	Indirect

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: Reflects decrease of 95,832 shares to correct for the inadvertent inclusion as directly held shares, in Reporting Person's Form 4 filed on February 23, 2010, of the same number of shares already reflected as indirectly held shares.

F3: Disposition to issuer of option, exempt from Section 16(b) under Rule 16b-3(e).