Exhibit 99.1

Steel Dynamics Reports Third Quarter 2013 Earnings

FORT WAYNE, INDIANA, October 16, 2013 / PRNewswire / Steel Dynamics, Inc. (NASDAQ/GS: STLD) today announced third quarter net income of $57 million, or $0.25 per diluted share, on net sales of $1.9 billion. By comparison, prior year third quarter net income was $13 million, or $0.06 per diluted share, on net sales of $1.7 billion, and sequential second quarter 2013 net income was $29 million, or $0.13 per diluted share, on net sales of $1.8 billion. In the nine months ended September 30, 2013 net income was $135 million, or $0.59 per diluted share, on net sales of $ 5.5 billion.  By comparison, in the nine months ended September 30, 2012 net income was $103 million, or $0.47 per diluted share, on net sales of $5.6 billion.

The company’s prior year financial results included unique charges related to refinancing expenses and non-cash impairment charges.  Excluding these items, the company’s adjusted earnings per diluted share would have been $0.15 for the third quarter 2012 and $0.59 for the nine months ended September 30, 2012.

“Our consolidated operating income increased 64 percent to $113 million for the third quarter 2013, as compared to the second quarter of this year,” said Chief Executive Officer, Mark Millett.  “Stronger steel sheet pricing combined with increased overall steel shipments, provided significant improvement to our third quarter financial results, as operating income from our steel operations sequentially increased $61 million.  We continued to see meaningful improvement in galvanized and painted sheet product demand.  The automotive market remained strong and the steel consuming manufacturing market, such as HVAC and appliance, rose in concert with the improved residential construction market.  Although volumes have increased, customer buying patterns continue to reflect a preference to manage relatively low inventory levels.  Additionally, the continued modest growth in the overall construction market benefited our structural steel and fabrication businesses, as evidenced by sequentially higher shipments and profitability.

“Operating income for our metals recycling operations decreased 29 percent to $11 million in the third quarter 2013, as compared to the second quarter of this year, which was the result of decreased ferrous metal spread, as increased ferrous volume did not offset the decline in market prices.  Profitability from our Midwest operations was actually slightly improved; however the continued industry overcapacity of shredding locations in the Southeast resulted in deterioration in earnings for those locations.”

Third Quarter Review

Third quarter 2013 shipments across the company’s operating platforms increased as compared to the sequential quarter. Operating income for the company’s steel operations increased to $149 million, or 69 percent as compared to the second quarter 2013, primarily due to an increase in metal spread as a result of both higher average steel selling prices and a nominal decrease in the average scrap cost per ton melted.

The company’s steel mill production utilization rate was 89 percent in the third quarter 2013, compared to 83 percent in the second quarter of 2013.  The Structural and Rail Division continued to improve production utilization as structural steel shipments increased 17 percent over the sequential quarter. The average selling price per ton for the company’s steel operations increased $13 to $794 in the third quarter 2013, and the average ferrous scrap cost per ton melted decreased $5 per ton.  Operating income attributable to the company’s steel sheet operations increased 92 percent as compared to the sequential quarter and earnings from long product operations increased 46 percent.

Sequential operating income for the company’s metals recycling operations decreased in the third quarter of 2013 to $11 million, as compared to $16 million.  Reduced earnings were the result of decreased average ferrous metal spreads in the third quarter, which more than offset the benefit of a ten percent increase in volume.  Generally, sequential earnings associated with nonferrous materials improved modestly during the third quarter as volume increased four percent and margins increased slightly.

The impact of losses from the company’s Minnesota operations for third quarter 2013 consolidated net income was $10.6 million, or $0.04 per diluted share, as compared to a loss of $9.3 million, or $0.04 per diluted share in the second quarter 2013.  The iron concentrate plant continues to operate as designed, providing raw material to the iron nugget plant at a cash cost below $50 per metric ton.  As noted in the company’s recent earnings guidance, production rates and plant availability at the iron nugget plant improved during the quarter, meeting current expectations.  However, at higher production rates, product yield has unexpectedly deteriorated.  Given the increase in costs related to the unforeseen yield impact and current pig iron prices, profitability related to the Minnesota operations is expected to approach a monthly cash breakeven before the end of 2013, but not to achieve pre-tax breakeven in that same timeframe.  Having achieved near-term production targets, the focus is now to reduce the overall cost of production.

Year to Date Comparison

Consolidated net sales were lower for the nine months ended September 30, 2013, at $5.5 billion, compared to $5.6 billion for the same period in 2012, as a result of lower average steel product pricing combined with both lower product pricing and decreased volumes in the company’s metals recycling operations.  Consolidated operating income decreased $18 million, or 6 percent, as declines in average steel prices more than offset the benefit of reduced scrap costs in the company’s steel operations.

The average selling price per ton shipped for the company’s steel operations in the nine months ended September 30, 2013 was $788, a decrease of $59 per ton as compared to the same period in 2012. The average ferrous cost per ton melted was $38 lower than the comparative 2012 period.

Outlook

“We are optimistic, as the demand for high-quality steel products continues to improve”, Millett said.  “The automotive market remains strong, and manufactured goods continue to strengthen.  We remain cautiously optimistic about the nonresidential construction market, as evidence of increased demand is shown by improved shipments of our structural and fabricated steel products.  However, we recognize the political environment within the U.S. concerning fiscal issues could have a limiting or negative impact on any continued improvement if not resolved in a timely manner.  In addition to improved market momentum, we are on schedule to complete two more sizable organic growth projects before the end of 2013:  a 325,000 ton capacity expansion at our Engineered Bar Products Division and a product capability expansion into premium rail at our Structural and Rail Division.  We are confident that with our exceptional team, and our superior, low-cost operating culture, we are uniquely prepared to capitalize on the opportunities ahead.”

Summary Operating Information

The following tables highlight operating results for each of the company’s primary operating platforms. References to operating income in the following paragraphs exclude profit-sharing expenses and amortization pertaining to intangible assets.  Dollar amounts are in thousands, excluding per ton data.

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, rebar, rail, and specialty shapes.

Metals Recycling and Ferrous Resources Operations

This segment principally includes the company’s metals recycling operations (OmniSource Corporation), a liquid pig iron production facility (Iron Dynamics), and the company’s Minnesota operations.

Steel Fabrication Operations

Steel fabrication operations include New Millennium Building Systems, which fabricates steel joists, trusses, and decking used in the construction of non-residential buildings.

About Steel Dynamics, Inc.

Steel Dynamics, Inc. is one of the largest domestic steel producers and metals recyclers in the United States based on estimated annual steelmaking and metals recycling capability, with annual sales of $7.3 billion in 2012, over 6,700 employees, and manufacturing facilities primarily located throughout the United States (including five steel mills, six steel processing facilities, two iron production facilities, over 90 metals recycling locations and six steel fabrication plants).

Forward-Looking Statement

This press release contains some predictive statements about future events, including statements related to conditions in the steel and metallic scrap markets, Steel Dynamics’ revenues, costs of purchased materials, future profitability and earnings, and the operation of new or existing facilities. 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. These statements speak only as of this date and are based upon information and assumptions, which we consider reasonable as of this date, concerning our businesses and the environments in which they operate. Such predictive statements are not guarantees of future performance, and we undertake no duty to update or revise any such statements. Some factors that could cause such forward-looking statements to turn out differently than anticipated include: (1) the effects of a recurrent slowing economy on industrial demand; (2) changes in economic conditions, either generally or in any of the steel or scrap-consuming sectors which affect demand for our products, including the strength of the non-residential and residential construction, automotive, appliance, and other steel-consuming industries; (3) fluctuations in the cost of key raw materials (including steel scrap, iron units, and energy costs) and our ability to pass-on any cost increases; (4) the impact of domestic and foreign import price competition; (5) risks and uncertainties involving product and/or technology development; and (6) occurrences of unexpected plant outages or equipment failures.

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. These are available publicly on the SEC Web site, www.sec.gov, and on the Steel Dynamics Web site, www.steeldynamics.com.

Conference Call and Webcast

On Thursday, October 17, 2013, at 10:00 a.m. Eastern Time, Steel Dynamics will host a conference call with investors and analysts to discuss the company’s third quarter operating and financial results.  We invite you to listen to the live audiocast of the conference call accessible from our website (http://www.steeldynamics.com), or via telephone (the conference call number may also be obtained on our website).  A replay of the discussion will be available on our website until midnight on October 24, 2013.  A podcast of the event will also be available and can be downloaded from our website.

Contact:  Marlene Owen, Director Investor Relations —+1.260.969.3500

Steel Dynamics, Inc.

CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

(in thousands, except per share data)

(Note 1)  Excludes the impact of the 5.125% convertible senior notes from net income (numerator) and share equivalents outstanding (denominator) for the three months ended September 30, 2012 and three months ended June 30, 2013, as the impact to diluted earnings per share is anti-dilutive.

Steel Dynamics, Inc.

UNAUDITED SUPPLEMENTAL OPERATING INFORMATION

(dollars in thousands)

(Note 1) Segment operating income (loss) excludes profit sharing expense.

Steel Dynamics, Inc.

CONSOLIDATED BALANCE SHEETS

(in thousands)

Steel Dynamics, Inc.

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

(in thousands)