Exhibit 99.1

Steel Dynamics Reports Third Quarter 2017 Results

FORT WAYNE, INDIANA, October 18, 2017 / PRNewswire / Steel Dynamics, Inc. (NASDAQ/GS: STLD) today announced third quarter 2017 financial results.  The company reported third quarter 2017 net sales of $2.4 billion and net income of $153 million, or $0.64 per diluted share, which includes debt refinancing and repayment charges of $0.02 per diluted share.  Excluding these items, the company’s third quarter 2017 adjusted net income was $158 million, or $0.66 per diluted share.

Comparatively, prior year third quarter net sales were $2.1 billion, with net income of $157 million, or $0.64 per diluted share, which includes a litigation settlement charge of approximately $5 million (pretax).  Excluding this item, prior year third quarter adjusted net income was $160 million, or $0.65 per diluted share.  Sequential second quarter 2017 net sales were $2.4 billion, with net income of $154 million, or $0.63 per diluted share.

“The team delivered a solid performance for the third quarter 2017 despite the continued high levels of steel imports,” said Mark D. Millett, President and Chief Executive Officer. “Our third quarter 2017 income from operations was $271 million, a sequential increase of $6 million, and trailing twelve month adjusted EBITDA remained strong at $1.4 billion.

“Elevated levels of steel imports persisted during the quarter, hindering the ability for domestic steel prices to keep pace with raw material costs.  Despite reported low levels of steel service center inventory, we believe steel traders built inventory at the ports ahead of potential domestic trade actions, which resulted in an overhang position for flat roll steel during recent months.  This oversupply resulted in periods of weaker customer orders.  The increase in our sequential earnings was principally the result of improved engineered bar, structural and merchant steel shipments.  Underlying demand from the construction sector appeared to remain strong, and the energy sector was stable.  Conversely, demand from the domestic automotive sector softened, but our steel operations continue to gain market share somewhat mitigating the impact.

“Third quarter 2017 operating income from our metals recycling platform aligned with the strong first half 2017 performance, derived from steady shipments and ferrous metal spread expansion as increased scrap exports supported higher average quarterly selling values. Earnings from our fabrication operations also improved in the quarter.  The fabrication group achieved another quarter of record shipments, and maintains a strong order backlog.  We believe this is a solid indicator that the non-residential construction market is continuing a positive growth profile,” concluded Millett.

Additional Third Quarter 2017 Comments

Third quarter 2017 operating income for the company’s steel operations increased two percent, or $6 million, to $280 million sequentially, based on higher shipments from our long products divisions outpacing metal spread compression.  The third quarter 2017 average external selling price for the company’s steel operations decreased $1 to $778 per ton.  The average ferrous scrap cost per ton melted increased $2 to $305 per ton.

Third quarter 2017 operating income attributable to the company’s flat roll products decreased three percent when compared to the sequential second quarter, based on slightly lower shipments and metal spread compression, as average scrap costs increased more than average selling values.  Operating income from long products increased 34 percent as a result of a six percent increase in shipments, notably for engineered bar, structural and merchant steel products.  However, structural and merchant steel volumes still remain under pressure from excess domestic production capability, coupled with elevated import levels.  The company’s steel production utilization rate was 92 percent in the third quarter 2017, compared to 91 percent in the sequential second quarter and compared to the estimated third quarter domestic industry utilization rate of 75 percent.

Third quarter 2017 operating income from the company’s metals recycling operations was $21 million, compared to $20 million in the sequential second quarter, as a result of improved average quarterly ferrous sales price and somewhat steady shipments.

The company’s fabrication operations recorded third quarter 2017 operating income of $22 million, compared to sequential second quarter results of $20 million.  The platform achieved a third consecutive quarter of record shipments and average product pricing remained steady.

During the third quarter 2017, the company issued $350 million of new 4.125% senior notes due 2025 to repay $350 million of its existing 6.375% senior notes due 2022.  At September 30, 2017, the company had repaid $183 million of the existing senior notes, and repaid the remaining amount of $167 million on October 13, 2017.  After giving effect to the October repayment, total debt of $2.4 billion remained consistent with the sequential second quarter and liquidity remained strong at $2.1 billion, with $935 million in cash and $1.2 billion of available funding under the revolving credit facility. These transactions extended the company’s overall debt maturity profile, and will provide an estimated annual interest savings of approximately $8 million.

Year-to-Date September 30, 2017 Comparison

For the nine months ended September 30, 2017, net income was $508 million, or $2.09 per diluted share, on net sales of $7.2 billion, as compared to net income of $362 million, or $1.48 per diluted share, on net sales of $5.9 billion for the same period in 2016.  Year-to-date 2017 net sales increased 23 percent.  Although all platforms experienced increased revenues, the overall improvement was driven by higher average steel product pricing and shipments.  Year-to-date 2017 operating income increased $199 million, or 30 percent, to $871 million, based on improved earnings of $183 million from the company’s steel operations and $32 million from its metals recycling platform. The average year-to-date selling price for the company’s steel operations increased $116 to $767 per ton.  The average year-to-date ferrous scrap cost per ton melted increased $71 to $291 per ton.  Additionally, the metals recycling operations continued to optimize administrative and operating costs, more than doubling operating income year-to-date 2017 compared to the same period in the prior year.

During the nine months ended September 30, 2017, the company generated strong cash flow from operations of $548 million and repurchased $237 million of its common stock.

Outlook

“Despite a somewhat noisy market environment related to continued high levels of steel imports, we remain optimistic that macroeconomic and market conditions are in place to benefit domestic steel consumption in 2018,” said Millett.  “Although U.S. automotive production has peaked, we believe North American automotive steel consumption will be steady, and that there will be continued additional growth in the energy and construction sectors, especially for larger, public sector infrastructure projects.

“We continue to reinvest in our existing facilities through equipment upgrades and further product diversification.  During the fourth quarter 2017, we plan to complete a $29 million replacement and upgrade of two ladle furnace cranes at our Butler Flat Roll Division, including a facility expansion to improve logistics.  We also plan to complete a $10 million upgrade of the hot strip mill at our Columbus Flat Roll Division, further diversifying our value-added flat roll steel product capabilities.  The planned upgrades require longer than typical outages, which will result in higher costs and lower shipments, reducing potential fourth quarter 2017 pretax earnings by an estimated $25 million.

“Our financial position continues to strengthen through strong cash flow generation and the execution of our long-term strategy. We are well-positioned for growth, and remain focused on delivering shareholder value through organic and strategic growth opportunities,” concluded Millett.

Conference Call and Webcast

Steel Dynamics, Inc. will hold a conference call to discuss third quarter 2017 operating and financial results on Thursday, October 19, 2017, at 10:00 a.m. Eastern Time.  You may access the call and find dial-in information on the Investors section of the company’s website at www.steeldynamics.com.  A replay of the call will be available on our website until 11:59 p.m. Eastern Time on October 24, 2017.

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 facilities located throughout the United States, and in Mexico.  Steel Dynamics produces steel products, including hot roll, cold roll, and coated sheet steel, structural steel beams and shapes, rail, engineered special-bar-quality steel, cold finished steel, merchant bar products, specialty steel sections and steel joists and deck.  In addition, the company produces liquid pig iron and processes and sells ferrous and nonferrous scrap.

Note Regarding Non-GAAP Financial Measures

The company reports its financial results in accordance with U.S. generally accepted accounting principles (GAAP). Management believes that Adjusted Operating Income, Adjusted Net Income, Adjusted Diluted Earnings Per Share, EBITDA and Adjusted EBITDA, non-GAAP financial measures, provide additional meaningful information regarding the company’s performance and financial strength. Non-GAAP financial measures should be viewed in addition to, and not as an alternative for, the company’s reported results prepared in accordance with GAAP.  In addition, because not all companies use identical calculations, EBITDA included in this release may not be comparable to similarly titled measures of other companies.

Forward-Looking Statements

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, which we generally precede or accompany by such typical conditional words as “anticipate,” “intend,” “believe,” “estimate,” “plan,” “seek,” “project” or “expect,” or by the words “may,” “will,” or “should,” 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 uncertain economic conditions; (2) cyclical and changing industrial demand; (3) changes in conditions in any of the steel or scrap-consuming sectors of the economy which affect demand for our products, including the strength of the non-residential and residential construction, automotive, appliance, pipe and tube, and other steel-consuming industries; (4) 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; (5) the impact of domestic and foreign import price competition; (6) unanticipated difficulties in integrating or starting up new or acquired businesses; (7) risks and uncertainties involving product and/or technology development; and (8) occurrences of unexpected plant outages or equipment failures.

More specifically, we refer you to Steel Dynamics’ 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 under the headings Special Note Regarding Forward-Looking Statements and Risk Factors, 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 website, www.sec.gov, and on the Steel Dynamics website, www.steeldynamics.com: Investors: SEC Filings.

Contact:  Tricia Meyers, Investor Relations Manager— +1.260.969.3500

Steel Dynamics, Inc.

CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

(in thousands, except per share data)

Steel Dynamics, Inc.

CONSOLIDATED BALANCE SHEETS

(in thousands)

Steel Dynamics, Inc.

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

(in thousands)

Steel Dynamics, Inc.

SUPPLEMENTAL INFORMATION

(dollars in thousands)