FOR IMMEDIATE RELEASE

ZOLTEK REPORTS FOURTH QUARTER/FISCAL YEAR RESULTS

ST. LOUIS, MISSOURI – December 16, 2013 – Zoltek Companies Inc. (Nasdaq: ZOLT) today reported financial results for the fourth quarter fiscal year-end results for 2013.

For the fourth quarter of fiscal 2013, ended September 30, 2013, Zoltek reported net sales of $41.0 million, compared to $44.2 million in the fourth quarter of fiscal 2012. Zoltek reported operating income of $1.7 million for the latest quarter and a net loss of ($0.2) million. In the fourth quarter of the previous fiscal year, Zoltek reported operating income of $5.3 million and net income of $4.2 million, or $0.13 per share.

For the fiscal year as a whole, Zoltek’s net sales decreased 25% to $140.5 million in fiscal 2013 from $186.3 million in fiscal 2012. In fiscal 2013, Zoltek reported operating income of $8.1 million and net income of $5.2 million, or $0.15 per share, which compares to operating income of $25.6 million and net income of $22.9 million, or $0.67 per share, in fiscal 2012.

Zoltek will not be hosting a conference call in conjunction with this earnings announcement.

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This press release contains certain statements that constitute “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. The words “expect,” “believe,” “goal,” “plan,” “intend,” “estimate,” and similar expressions and variations thereof are intended to specifically identify forward-looking statements. Those statements include statements regarding the intent, belief or current expectations of us, our directors and officers with respect to, among other things: (1) our financial prospects; (2) our growth strategy and operating strategy, including our focus on facilitating acceleration of the introduction and development of mass market applications for carbon fibers; and (3) our current and expected future revenue. This press release also contains statements that are based on the current expectations of our company. You are cautioned that any such forward-looking statements are not guarantees of future performance and involve risks and uncertainties, and that actual results may differ materially from those projected in the forward-looking statements as a result of various factors. The factors that might cause such differences include, among others, our ability to: (1) successfully adapt to recessionary conditions in the global economy and substantial volatility in order rates from our wind energy customers, including our principal customer Vestas Wind Systems; (2) penetrate existing, identified and emerging markets, including entering into new supply agreements with large volume customers; (3) continue to improve efficiency at our manufacturing facilities on a timely and cost-effective basis; (4) successfully add new planned capacity for the production of carbon fiber, prepregs and precursor raw materials and meet our obligations under long-term supply agreements; (5) operate profitably; (6) increase or maintain our borrowing at acceptable costs; (7) manage changes in customers’ forecasted requirements for our products; (8) continue investing in application and market development for a range of applications; (9) manufacture low-cost carbon fibers and profitably market them despite fluctuations in raw material and energy costs; (10) successfully operate our Mexican facility to produce acrylic fiber precursor and carbon fibers; (11) successfully continue operations at our Hungarian facility if natural gas supply disruptions occur; (12) successfully prosecute patent litigation; (13) successfully facilitate adoption of our carbon fibers by the auto industry for use in high-volume applications; (14) establish and grow prepreg capacity; (15) speed development of low-cost carbon fiber sheet molding compounds for the automotive industry pursuant to our global collaborative partnership with Magna Exteriors and Interiors; (16) resolve possible disputes with a group of shareholders that filed a Schedule 13D reporting beneficial ownership of an aggregate of approximately 10.1% of our outstanding common stock, including the group’s request for a special shareholders meeting to remove the current Board of Directors and elect new directors; (17) manage and respond to matters relating to our proposed Merger with Toray Industries, Inc., including without limitation (a) the occurrence of any event, change or other circumstances that could give rise to termination of the Merger Agreement before the Merger is completed; (b) the outcome of any legal proceedings instituted against Zoltek and others following announcement of the Merger Agreement; (c) our ability to complete the proposed Merger due to the failure of Zoltek, Toray or Merger Sub to satisfy the conditions to the Merger, including, but not limited to, obtaining the approval of our shareholders, antitrust approval and other closing conditions; (d) potential employee retention difficulties as a result of the proposed Merger; (e) disruption of our operations as a result of the Merger; and (f) our ability to realize the benefits of the Merger; and; and (18) manage the risks identified under "Risk Factors" in our filings with the SEC. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified, you should not rely upon forward-looking statements as predictions of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements.

For further information contact:

Andrew Whipple, CFO

3101 McKelvey Road 

St. Louis, MO 63044

(314) 291-5110