Exhibit 99.1

Steel Dynamics Reports Third Quarter 2011 Results

FORT WAYNE, INDIANA, October 17, 2011— Steel Dynamics, Inc. (NASDAQ-GS: STLD) today announced third quarter net income of $43 million, or $0.19 per diluted share, on net sales of $2.0 billion. By comparison, third quarter 2010 net income was $19 million, or $0.09 per diluted share, on net sales of $1.6 billion, and second quarter 2011 net income was $99 million, or $0.43 per diluted share, on net sales of $2.1 billion.

Third quarter 2011 steel shipments were 1.5 million tons, 12 percent higher than the third quarter of 2010 and 1 percent higher than the second quarter of 2011. The average external steel selling price for the third quarter (including sales by The Techs) increased $115 per ton shipped to $897 from the third quarter 2010 average sales price of $782, and decreased $50 per ton shipped from the second quarter 2011 average sales price of $947 per ton.

Based on the tons of scrap melted at the five steel mills, the third quarter’s average ferrous scrap cost per ton melted increased $79 compared to the third quarter of 2010, and increased $5 compared to the second quarter of 2011.

OmniSource’s ferrous shipments in the third quarter were 1.5 million gross tons, 9 percent higher than the third quarter of 2010, but 5 percent lower than the second quarter of 2011. OmniSource provided 53 percent of the ferrous scrap purchased by SDI’s steel mills during the third quarter.  Third quarter non-ferrous shipments were 270 million pounds, 5 percent higher than the third quarter of 2010, and 6 percent higher than the second quarter of 2011.

“Quarter over quarter operating income was significantly impacted by decreased flat rolled earnings, ” said Keith Busse, Chairman and CEO. “Despite relatively unchanged volumes, earnings from our flat rolled operations declined 60 percent in the third quarter as declines in pricing were matched with increased raw material costs, resulting in significant margin compression.  Our average flat rolled selling price per ton shipped decreased $95 in the third quarter. Orders remain fairly consistent, and we currently believe flat rolled pricing has reached a current cycle bottom. The Flat Roll mill operated at an estimated production capacity of 93 percent during the third quarter.”

Operating income from the company’s steel operations was $139 million, or $96 per ton shipped in the third quarter of 2011, an increase of $51 million, or $28 per ton compared to the same quarter of 2010, but a decrease of $78 million, or $57 per ton compared to the second quarter of 2011.

“Business at the Engineered Bar Products Division remains strong,” continued Busse, “and our team is executing very well. The mill’s production of 167,000 tons in the third quarter was at a rate exceeding its theoretical annual capacity of 625,000 tons. During the third quarter our Structural and Rail Division achieved a 50 percent utilization rate, its highest production rate since the recession lows of 2009. Third quarter rail shipments were 31,000 tons, bringing year-to-date rail shipments to 97,000 tons. Steel of West Virginia is also experiencing strong demand and operated at 90 percent of capacity during the third quarter.”

Third quarter operating losses for the fabrication segment narrowed to $250,000, as compared to $500,000 in the third quarter of 2010, and $1.6 million in the second quarter of 2011.

“Operating income for OmniSource was $11 million in the third quarter, a decrease of $11 million in comparison to the third quarter of 2010, and a decrease of $7 million in comparison to the second quarter of 2011,” said Mark Millett, President and Chief Operating Officer.  “In spite of weaker sequential volumes, earnings from our ferrous operations improved in the third quarter through margin expansion.  However, the unexpected dramatic slide in copper, aluminum and nickel prices during late September resulted in negative earnings from our non-ferrous operations which more than offset the quarter over quarter ferrous improvement.  We recorded non-cash, unrealized losses of $6 million, or approximately $0.02 per diluted share after-tax, in late September associated specifically with marking our fixed price forward purchase contracts to lower market values.  However, our complete hedging program, including the offset from fixed price forward purchase contracts, resulted in a non-cash, unrealized hedging gain of $2 million in the third quarter.”

The impact of Mesabi Nugget start-up losses on the company’s third quarter 2011 consolidated pre-tax earnings was unchanged from the second quarter at $13 million, or approximately $0.03 per diluted share, after-tax.  Third quarter production of iron nuggets was 33,000 metric tons, a decrease from the 38,000 metric tons produced in the second quarter, due to a planned three week September outage  needed to install equipment to improve plant utilization going forward.

“I am pleased to report that we have made progress in assuring a low-cost, secure alternative future supply of iron concentrate for use at Mesabi Nugget,” Millett said. “One of the uncertainties of the project has been the timing related to issuance of the necessary mining permits from the State of Minnesota, which is necessary for us to benefit from lower cost iron concentrate in the production process.   Progress continues to be made, but we currently believe the earliest we might receive the permit is the end of 2012.  During the third quarter, as an alternative and complement to mining, we entered into a joint-venture agreement with Magnetation, Inc. to form a business to supply sufficient iron concentrate to fully meet the needs of the Mesabi Nugget plant at full utilization.  We anticipate obtaining permits for this venture before the end of the year, and expect production to begin in the third quarter of 2012.  Iron Dynamics continues to provide a consistent supply of liquid pig iron to the Flat Roll Division. Its output, combined with our supply of iron nuggets, makes the company self-sufficient in providing iron resources to our Flat Roll mill.”

In September, the company also amended, restated and expanded its senior secured revolving credit facility from the prior $924 million level to a renewed five year $1.1 billion facility.  Combined with cash deposits of $457 million, the company achieved record liquidity of over $1.5 billion at September 30, 2011.  Subject to certain conditions, the company also has the opportunity to increase the facility size by an additional $400 million.

The company recorded other non-cash expenses of approximately $3.3 million, or approximately $0.01 per diluted share, after-tax, during the third quarter 2011, related to an equipment impairment charge and the write off of financing fees associated with the prior revolving credit facility.  In addition, in appreciation for the dedication and performance demonstrated by the company’s employees during the past two years, the company awarded each employee with a $1,000 cash bonus during the third quarter, which totaled $5.8 million, or approximately $0.02 per diluted share, after-tax.

“Looking ahead to the fourth quarter of 2011,” Busse said, “we believe the economic climate will remain challenging in light of decreased consumer confidence, the uncertain domestic political landscape and the European debt crisis.  To a large degree these elements are out of our control; however, we remain confident that with our low-cost manufacturing structure, exceptional employee base, and superior operating culture, we are prepared to capitalize on all opportunities presented.  We will provide more definitive quantitative guidance regarding the fourth quarter in December.”

Third Quarter 2011 Reporting Segment Information

The following highlights third quarter 2011 results for each of SDI’s three primary reporting segments. References to segment operating income and operating income per ton in the following paragraphs exclude profit-sharing costs and amortization related to intangible assets.

Steel Operations. This segment includes five electric-arc-furnace steel mills and related steel finishing and processing facilities, including The Techs. The company’s steel operations produce flat-rolled steel, structural steel, merchant bars, special-bar-quality steel, rail, and specialty shapes. Steel operations represented 60 percent of the company’s third quarter 2011 external net sales and 61 percent of external net sales in the second quarter 2011. Third quarter 2011 net sales for steel operations were $1.3 billion on shipments of 1.5 million tons, compared to net sales of $1.0 billion on shipments of 1.3 million tons during the same period in 2010, and $1.4 billion in net sales on shipments of 1.5 million tons in the second quarter of 2011 (including intra-segment and intra-company sales). The average external steel selling price for the third quarter decreased $50 per ton to $897 from the second quarter 2011 average of $947. The third quarter’s average ferrous scrap cost per ton charged was $5 higher than the second quarter of 2011. Third quarter operating income for the steel segment was $139 million, or $96 per ton shipped, compared to $88 million, or $68 per ton, in the third quarter of 2010, and $217 million, or $153 per ton, in the second quarter of 2011.

Metals Recycling and Ferrous Resources.  This segment principally includes the company’s metals recycling operations (OmniSource Corporation), liquid pig iron manufacturing facility (Iron Dynamics), and iron nugget manufacturing start-up facility (Mesabi Nugget, which is 81 percent company owned). Third quarter net sales (including intra-segment and intra-company sales) and operating income for the segment were $1.1 billion and $3.7 million, respectively, as compared to $805 million and $9.4 million during the third quarter of 2010, and $1.1 billion and operating income of $11 million in the second quarter of 2011. The segment represented 35 percent of the company’s external net sales for both the second and third quarters of 2011.

OmniSource’s third quarter 2011 ferrous shipments were 1.5 million gross tons and non-ferrous shipments were 270 million pounds, compared to ferrous shipments of 1.4 million gross tons and non-ferrous shipments of 257 million pounds for the third quarter of 2010, and ferrous shipments of 1.6 million gross tons and non-ferrous shipments of 255 million pounds for the second quarter of 2011. OmniSource’s ferrous scrap shipments to SDI’s steel mills were 44 percent of its ferrous scrap shipments during the third quarter versus 42 percent in the second quarter of 2011. During the third  quarter, OmniSource supplied 646,000 gross tons of ferrous scrap to SDI’s steel operations, or approximately 53 percent of the tonnage of ferrous scrap purchased by the mills. Operating income for OmniSource for the third quarter of 2011 was $11 million as compared to $22 million during the third quarter of 2010 and $18 million in the second quarter of 2011.

Steel Fabrication Operations.  The New Millennium Building Systems steel fabrication operations fabricate steel joists, trusses, and decking used in the construction of non-residential buildings.  Fabrication operations represented 4 percent of the company’s external net sales for the third quarter of 2011 as compared to 3 percent for the second quarter.

Third quarter 2011 net sales for fabrication operations were $83 million on shipments of 65,000 tons, compared to $54 million on shipments of 47,000 tons during the same period in 2010, and $62 million on shipments of 48,000 tons during the second quarter of 2011 (including intra-company sales and shipments). Third quarter operating losses for the fabrication segment narrowed to $250,000, as compared to $500,000 in the third quarter of 2010, and $1.6 million in the second quarter of 2011.

Forward-Looking Statements

This press release contains some predictive statements about future events, including statements related to conditions in the steel and scrap metal markets, Steel Dynamics’ revenues, costs, future earnings, and the operation of new or existing facilities or technologies. These statements are intended to be made as “forward-looking,” subject to many risks and uncertainties, within the safe harbor protections of the Private Securities Litigation Reform Act of 1995. Such predictive statements are not guarantees of future performance, and actual results could differ materially from our current expectations.

Factors that could cause such predictive statements to turn out other than as anticipated or predicted include, among others: the effects of a prolonged or deepening recession on industrial demand; conditions in such steel consuming sectors as the automotive, consumer appliance or construction industries; the impact of domestic or foreign import price competition; difficulties in integrating or in realizing anticipated values from acquired businesses; risks and uncertainties involving new products or new technologies; changes in the availability or cost of steel scrap or scrap substitute materials; increases in energy costs; occurrence of unanticipated equipment failures and plant outages; labor unrest; and the effect of the elements on production or consumption.

More specifically, we refer you to SDI’s more detailed explanation of these and other factors and risks that may cause such predictive statements to turn out differently, as set forth in our most recent Annual Report on Form 10-K, in our quarterly reports on Form 10-Q, or in other reports which we from time to time file with the Securities and Exchange Commission, available publicly on the SEC Web site, www.sec.gov, and on the Steel Dynamics Web site, www.steeldynamics.com.

Forward-looking or predictive statements we make are based upon information and assumptions concerning our businesses and the environments in which they operate, which we consider reasonable as of the date on which these statements are made. Due to the foregoing risks and uncertainties however, as well as matters beyond our control which can affect forward-looking statements, we caution you that these statements speak only as of the date hereof.

Conference Call and Webcast

On Tuesday, October 18, 2011, at 10:00 a.m. Eastern time, Steel Dynamics will host a conference call in which management will discuss third quarter results. You are invited to listen to the live audio broadcast of the conference call over the Internet, accessible from the Steel Dynamics Web site:  www.steeldynamics.com

Dial-in information is available on our Web site. An audio replay of the Webcast and a downloadable podcast will be available from the SDI Web site. No telephone replay will be available.

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