<PAGE>

                                                                Exhibit 4.8

                                                                  EXHIBIT C
                                                                  ---------

NEITHER THESE SECURITIES NOR THE SECURITIES INTO WHICH THESE SECURITIES ARE
EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION
OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM
REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES
ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN
EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN
AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE
REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH
APPLICABLE STATE SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL
TO THE TRANSFEROR TO SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY
ACCEPTABLE TO THE COMPANY. THESE SECURITIES AND THE SECURITIES ISSUABLE UPON
EXERCISE OF THESE SECURITIES MAY BE PLEDGED IN A MANNER CONSISTENT WITH THE
SECURITIES ACT IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT SECURED BY SUCH
SECURITIES.

                           ZOLTEK COMPANIES, INC.

                                   WARRANT

Warrant No. [ ]               Date of Original Issuance: January [ ], 2004

         Zoltek Companies, Inc., a Missouri corporation (the "COMPANY"),
hereby certifies that, for value received, [ ] or its registered assigns
(the "HOLDER"), is entitled to purchase from the Company up to a total of
[ ] shares of common stock, par value $0.01 per share (the "COMMON STOCK"),
of the Company (each such share, a "WARRANT SHARE" and all such shares, the
"WARRANT SHARES") at an exercise price equal to [$ ](1) per share (as adjusted
from time to time as provided in Section 9, the "EXERCISE PRICE"), at any
time and from time to time from and after the date hereof and through and
including January [__], 2008 (the "EXPIRATION DATE"), and subject to the
following terms and conditions:

<FN>
--------
(1) 110% of the average of the VWAP for the ten Trading Days
    immediately prior to the date of the Purchase Agreement or the
    Closing, whichever is less; provided, that (x) the Exercise Price
                                --------
    for those Holders who became party to the Purchase Agreement after
    December 19, 2003 and who are not officers or directors of the
    Company shall equal 110% of the average of the VWAP for the ten
    Trading Days immediately prior to the date of the Purchase
    Agreement or the date of the Closing, whichever is less, and (y)
    the Exercise Price for those Holders who became party to the
    Purchase Agreement after December 19, 2003 and who are officers or
    directors of the Company shall equal the greater of (1) 110% of the
    average of the VWAP for the ten Trading Days immediately prior to
    the date of the Purchase Agreement or the Closing, whichever is
    less, and (2) the closing bid price of the Common Stock on the
    Trading Day immediately prior to the date that such Holder became
    party to the Purchase Agreement.


<PAGE>
<PAGE>

         1.       Definitions. In addition to the terms defined elsewhere
                  -----------
in this Warrant, capitalized terms that are not otherwise defined herein
shall have the meanings given to such terms in the Securities Purchase
Agreement of even date herewith to which the Company and the original Holder
are parties (the "PURCHASE AGREEMENT").

         2.       Registration of Warrant. The Company shall register this
                  -----------------------
Warrant, upon records to be maintained by the Company for that purpose (the
"WARRANT REGISTER"), in the name of the record Holder hereof from time to
time. The Company may deem and treat the registered Holder of this Warrant
as the absolute owner hereof for the purpose of any exercise hereof or any
distribution to the Holder, and for all other purposes, absent actual notice
to the contrary.

         3.       Registration of Transfers. The Company shall register
                  -------------------------
the transfer of any portion of this Warrant in the Warrant Register, upon
surrender of this Warrant, with the Form of Assignment attached hereto duly
completed and signed, to the Company at its address specified herein. Upon
any such registration or transfer, a new Warrant to purchase Common Stock,
in substantially the form of this Warrant (any such new Warrant, a "NEW
WARRANT"), evidencing the portion of this Warrant so transferred shall be
issued to the transferee and a New Warrant evidencing the remaining portion
of this Warrant not so transferred, if any, shall be issued to the
transferring Holder. The acceptance of the New Warrant by the transferee
thereof shall be deemed the acceptance by such transferee of all of the
rights and obligations of a holder of a Warrant.

         4.       Exercise and Duration of Warrants. This Warrant shall be
                  ---------------------------------
exercisable by the registered Holder at any time and from time to time on or
after the date hereof to and including the Expiration Date. At 6:30 p.m.,
New York City time on the Expiration Date, the portion of this Warrant not
exercised prior thereto shall be and become void and of no value, provided,
                                                                  --------
that if the closing sales price of the Common Stock on the Expiration Date
is greater than 102% of the Exercise Price on the Expiration Date, then this
Warrant shall be deemed to have been exercised in full (to the extent not
previously exercised) on a "cashless exercise" basis at 6:30 P.M. New York
City time on the Expiration Date. The Company may not call or redeem all or
any portion of this Warrant without the prior written consent of the Holder.

         5.       Delivery of Warrant Shares.
                  --------------------------

                  (a)      To effect exercises hereunder, the Holder shall
not be required to physically surrender this Warrant unless the aggregate
Warrant Shares represented by this Warrant is being exercised. Upon delivery
of the Exercise Notice to the Company (with the attached Warrant Shares
Exercise Log) at its address for notice set forth herein and upon payment of
the Exercise Price multiplied by the number of Warrant Shares that the
Holder intends to purchase hereunder, the Company shall promptly (but in no
event later than three Trading Days after the Date of Exercise (as defined
herein)) issue and deliver to the Holder, a certificate for the Warrant
Shares issuable upon such exercise, which, unless otherwise required by the
Purchase Agreement, shall be free of restrictive legends. The Company shall,
upon request of the Holder and subsequent to the date on which a
registration statement covering the resale of the Warrant Shares has been
declared effective by the Securities and Exchange Commission, use its best
efforts to deliver Warrant Shares hereunder electronically through the
Depository Trust Corporation or another established clearing corporation
performing similar


                                    -2-

<PAGE>
<PAGE>

functions, if available, provided, that, the Company may, but will not be
required to change its transfer agent if its current transfer agent cannot
deliver Warrant Shares electronically through the Depository Trust
Corporation. A "DATE OF EXERCISE" means the date on which the Holder shall
have delivered to Company: (i) the Exercise Notice (with the Warrant
Exercise Log attached to it), appropriately completed and duly signed and
(ii) if such Holder is not utilizing the cashless exercise provisions set
forth in this Warrant, payment of the Exercise Price for the number of
Warrant Shares so indicated by the Holder to be purchased.

                  (b)      If by the third Trading Day after a Date of
Exercise the Company fails to deliver the required number of Warrant Shares
in the manner required pursuant to Section 5(a), then the Holder will have
the right to rescind such exercise.

                  (c)      If by the third Trading Day after a Date of
Exercise the Company fails to deliver the required number of Warrant Shares
in the manner required pursuant to Section 5(a), and if after such third
Trading Day and prior to the receipt of such Warrant Shares, the Holder
purchases (in an open market transaction or otherwise) shares of Common
Stock to deliver in satisfaction of a sale by the Holder of the Warrant
Shares which the Holder anticipated receiving upon such exercise (a
"BUY-IN"), then the Company shall (1) pay in cash to the Holder the amount
by which (x) the Holder's total purchase price (including brokerage
commissions, if any) for the shares of Common Stock so purchased exceeds (y)
the amount obtained by multiplying (A) the number of Warrant Shares that the
Company was required to deliver to the Holder in connection with the
exercise at issue by (B) the closing bid price of the Common Stock at the
time of the obligation giving rise to such purchase obligation and (2) at
the option of the Holder, either reinstate the portion of the Warrant and
equivalent number of Warrant Shares for which such exercise was not honored
or deliver to the Holder the number of shares of Common Stock that would
have been issued had the Company timely complied with its exercise and
delivery obligations hereunder. The Holder shall provide the Company written
notice indicating the amounts payable to the Holder in respect of the
Buy-In.

                  (d)      The Company's obligations to issue and deliver
Warrant Shares in accordance with the terms hereof are absolute and
unconditional, irrespective of any action or inaction by the Holder to
enforce the same, any waiver or consent with respect to any provision
hereof, the recovery of any judgment against any Person or any action to
enforce the same, or any setoff, counterclaim, recoupment, limitation or
termination, or any breach or alleged breach by the Holder or any other
Person of any obligation to the Company or any violation or alleged
violation of law by the Holder or any other Person, and irrespective of any
other circumstance which might otherwise limit such obligation of the
Company to the Holder in connection with the issuance of Warrant Shares.
Nothing herein shall limit a Holder's right to pursue any other remedies
available to it hereunder, at law or in equity including, without
limitation, a decree of specific performance and/or injunctive relief with
respect to the Company's failure to timely deliver certificates representing
shares of Common Stock upon exercise of the Warrant as required pursuant to
the terms hereof.

         6.       Charges, Taxes and Expenses. Issuance and delivery of
                  ---------------------------
certificates for shares of Common Stock upon exercise of this Warrant shall
be made without charge to the Holder for any issue or transfer tax,
withholding tax, transfer agent fee or other incidental tax or expense in
respect of the issuance of such certificates, all of which taxes and
expenses shall be paid by the


                                    -3-

<PAGE>
<PAGE>

Company; provided, however, that the Company shall not be required to
pay any tax which may be payable in respect of any transfer involved in the
registration of any certificates for Warrant Shares or Warrants in a name
other than that of the Holder. The Holder shall be responsible for all other
tax liability that may arise as a result of holding or transferring this
Warrant or receiving Warrant Shares upon exercise hereof.

         7.       Replacement of Warrant. If this Warrant is mutilated,
                  ----------------------
lost, stolen or destroyed, the Company shall issue or cause to be issued in
exchange and substitution for and upon cancellation hereof, or in lieu of
and substitution for this Warrant, a New Warrant, but only upon receipt of
evidence reasonably satisfactory to the Company of such loss, theft or
destruction and customary and reasonable indemnity (which may include a
surety bond for any Holder other than the original Holder of the Warrant),
if requested. Applicants for a New Warrant under such circumstances shall
also comply with such other reasonable regulations and procedures and pay
such other reasonable third-party costs as the Company may prescribe. If a
New Warrant is requested as a result of a mutilation of this Warrant, then
the Holder shall deliver such mutilated Warrant to the Company as a
condition precedent to the Company's obligation to issue the New Warrant.

         8.       Reservation of Warrant Shares. The Company covenants that
                  -----------------------------
it will at all times reserve and keep available out of the aggregate of its
authorized but unissued and otherwise unreserved Common Stock, solely for
the purpose of enabling it to issue Warrant Shares upon exercise of this
Warrant as herein provided, the number of Warrant Shares which are then
issuable and deliverable upon the exercise of this entire Warrant, free from
preemptive rights or any other contingent purchase rights of persons other
than the Holder (taking into account the adjustments and restrictions of
Section 9). The Company covenants that all Warrant Shares so issuable and
---------
deliverable shall, upon issuance and the payment of the applicable Exercise
Price in accordance with the terms hereof, be duly and validly authorized,
issued and fully paid and nonassessable.

         9.       Certain Adjustments. The Exercise Price and number of
                  -------------------
Warrant Shares issuable upon exercise of this Warrant are subject to
adjustment from time to time as set forth in this Section 9.
                                                  ---------

                  (a)      Stock Dividends and Splits. If the Company, at
                           --------------------------
any time while this Warrant is outstanding, (i) pays a stock dividend on its
Common Stock or otherwise makes a distribution on any class of capital stock
that is payable in shares of Common Stock, (ii) subdivides outstanding
shares of Common Stock into a larger number of shares, or (iii) combines
outstanding shares of Common Stock into a smaller number of shares, then in
each such case the Exercise Price shall be multiplied by a fraction of which
the numerator shall be the number of shares of Common Stock outstanding
immediately before such event and of which the denominator shall be the
number of shares of Common Stock outstanding immediately after such event.
Any adjustment made pursuant to clause (i) of this paragraph shall become
effective immediately after the record date for the determination of
shareholders entitled to receive such dividend or distribution, and any
adjustment pursuant to clause (ii) or (iii) of this paragraph shall become
effective immediately after the effective date of such subdivision or
combination. If any event requiring an adjustment under this paragraph
occurs during the period that an Exercise

                                    -4-

<PAGE>
<PAGE>

Price is calculated hereunder, then the calculation of such Exercise Price
shall be adjusted appropriately to reflect such event.

                  (b)      Pro Rata Distributions. If the Company, at any
                           ----------------------
time while this Warrant is outstanding, distributes to all holders of Common
Stock (i) evidences of its indebtedness, (ii) any security (other than a
distribution of Common Stock covered by the preceding paragraph), (iii)
rights or warrants to subscribe for or purchase any security, or (iv) any
other asset (in each case, "DISTRIBUTED PROPERTY"), then, at the request of
any Holder delivered before the 90th day after the record date fixed for
determination of shareholders entitled to receive such distribution, the
Company will deliver to such Holder, within five Trading Days after such
request (or, if later, on the effective date of such distribution), the
Distributed Property that such Holder would have been entitled to receive in
respect of the Warrant Shares for which such Holder's Warrant could have
been exercised immediately prior to such record date. If such Distributed
Property is not delivered to a Holder pursuant to the preceding sentence,
then upon any exercise of the Warrant that occurs after such record date,
such Holder shall be entitled to receive, in addition to the Warrant Shares
otherwise issuable upon such conversion, the Distributed Property that such
Holder would have been entitled to receive in respect of such number of
Warrant Shares had the Holder been the record holder of such Warrant Shares
immediately prior to such record date. Notwithstanding the foregoing, this
Section 11(b) shall not apply to any distribution of rights or securities in
respect of adoption by the Company of a shareholder rights plan which events
shall be covered by the anti-dilution provisions of Section 9(a).

                  (c)      Fundamental Transactions. If, at any time while
                           ------------------------
this Warrant is outstanding, (1) the Company effects any merger or
consolidation of the Company with or into another Person, (2) the Company
effects any sale of all or substantially all of its assets in one or a
series of related transactions, (3) any tender offer or exchange offer
approved or authorized by the Board of Directors of the Company (whether by
the Company or another Person) is completed pursuant to which holders of
Common Stock are permitted to tender or exchange their shares for other
securities, cash or property, or (4) the Company effects any
reclassification of the Common Stock or any compulsory share exchange
pursuant to which the Common Stock is effectively converted into or
exchanged for other securities, cash or property (in any such case, a
"FUNDAMENTAL TRANSACTION"), then the Holder shall have the right thereafter
to receive, upon exercise of this Warrant, the same amount and kind of
securities, cash or property as it would have been entitled to receive upon
the occurrence of such Fundamental Transaction if it had been, immediately
prior to such Fundamental Transaction, the holder of the number of Warrant
Shares then issuable upon exercise in full of this Warrant (the "ALTERNATE
CONSIDERATION"). For purposes of any such exercise, the determination of the
Exercise Price shall be appropriately adjusted to apply to such Alternate
Consideration based on the amount of Alternate Consideration issuable in
respect of one share of Common Stock in such Fundamental Transaction, and
the Company shall apportion the Exercise Price among the Alternate
Consideration in a reasonable manner reflecting the relative value of any
different components of the Alternate Consideration. If holders of Common
Stock are given any choice as to the securities, cash or property to be
received in a Fundamental Transaction, then the Holder shall be given the
same choice as to the Alternate Consideration it receives upon any exercise
of this Warrant following such Fundamental Transaction. At the Holder's
option and request, any successor to the Company or surviving entity in such
Fundamental Transaction shall, either (1) issue to the Holder a new warrant
substantially in the form of this Warrant and consistent with

                                    -5-

<PAGE>
<PAGE>

the foregoing provisions and evidencing the Holder's right to purchase the
Alternate Consideration for the aggregate Exercise Price upon exercise
thereof, or (2) purchase the Warrant from the Holder for a purchase price,
payable in cash within five Trading Days after such request (or, if later,
on the effective date of the Fundamental Transaction), equal to the Black
Scholes value of the remaining unexercised portion of this Warrant on the
date of such request as well as assumptions reasonably mutually acceptable
to the Company and the Holder, provided, that for purposes of such
                               --------
calculation, the market price of the Common Stock shall be the closing bid
price of the Common Stock on the Trading Day immediately preceding the
public announcement of the Fundamental Transaction and the volatility factor
shall be determined by reference to the 12 month average industry volatility
measures. The terms of any agreement pursuant to which a Fundamental
Transaction is effected shall include terms requiring any such successor or
surviving entity to comply with the provisions of this paragraph (c) and
insuring that the Warrant (or any such replacement security) will be
similarly adjusted upon any subsequent transaction analogous to a
Fundamental Transaction.

                  (d)      Subsequent Equity Sales.(2)
                           -----------------------

                           (i)      While any portion of this Warrant is
outstanding, if the Company issues any shares of Common Stock or the Company
or any subsidiary thereof issues any rights, warrants, options or other
securities or debt that is convertible into, exchangeable for (any such
securities, "COMMON STOCK EQUIVALENTS") entitling any Person to acquire
shares of Common Stock, at a price per share less than the Exercise Price
(if the holder of the Common Stock or Common Stock Equivalent so issued
shall at any time, whether by operation of purchase price adjustments, reset
provisions, floating conversion, exercise or exchange prices or otherwise,
or due to warrants, options or rights issued in connection with such
issuance, be entitled to receive shares of Common Stock at a price less than
the Exercise Price, such issuance shall be deemed to have occurred for less
than the Exercise Price), then, at the option of the Holder for such
exercises as it shall indicate, the Exercise Price shall be adjusted to
equal the conversion, exchange or purchase price for such Common Stock or
Common Stock Equivalents (including any reset provisions thereof) at issue
and which adjusted Exercise Price shall continue for as long as this
Warrants remain outstanding. Such adjustment shall be made whenever such
Common Stock or Common Stock Equivalents are issued. The Company shall
notify the Holder in writing, no later than the Trading Day following the
issuance of any Common Stock or Common Stock Equivalent subject to this
section, indicating therein the applicable issuance price, or of applicable
reset price, exchange price, conversion price and other pricing terms.

                           (ii)     If, at any time while this Warrant is
outstanding, the Company or any Subsidiary issues Common Stock Equivalents
at a price per share that floats or resets or otherwise varies or is subject
to adjustment based on market prices of the Common Stock (a "FLOATING PRICE
SECURITY"), then for purposes of applying the preceding paragraph in
connection with any subsequent exercise, the Exercise Price will be
determined separately on each Exercise Date and will be deemed to equal the
lowest price per share at which any holder of such Floating Price Security
is entitled to acquire shares of Common Stock on such Exercise Date
(regardless of whether any such holder actually acquires any shares on such
date).

<FN>
--------
(2) This provision will not be in the Warrants issued to directors or
    officers of the Company.

                                    -6-

<PAGE>
<PAGE>

                           (iii)    Notwithstanding the foregoing, no
adjustment will be made under this Section 9(d) as a result of: (i) the
issuance of securities upon the exercise or conversion of any Common Stock
Equivalents issued by the Company prior to the date of this Agreement (but
will apply to any amendments, modifications and reissuances thereof), (ii)
the grant of options or warrants, or the issuance of additional securities,
under any duly authorized company stock option, stock incentive plan,
restricted stock plan or stock purchase plan in existence on the Closing
Date, (iii) the issuance of Common Stock in payment of interest on the
Debentures, or (iv) the issuance of Common Stock Equivalents pursuant to a
Strategic Transaction.

                  (e)      Number of Warrant Shares. Simultaneously with
                           ------------------------
any adjustment to the Exercise Price pursuant to paragraph (a) of this
Section, the number of Warrant Shares that may be purchased upon exercise of
this Warrant shall be increased or decreased proportionately, so that after
such adjustment the aggregate Exercise Price payable hereunder for the
adjusted number of Warrant Shares shall be the same as the aggregate
Exercise Price in effect immediately prior to such adjustment.

                  (f)      Calculations. All calculations under this
                           ------------
Section 9 shall be made to the nearest cent or the nearest 1/100th of a
---------
share, as applicable. The number of shares of Common Stock outstanding at
any given time shall not include shares owned or held by or for the account
of the Company, and the disposition of any such shares shall be considered
an issue or sale of Common Stock.

                  (g)      Notice of Adjustments. Upon the occurrence of
                           ---------------------
each adjustment pursuant to this Section 9, the Company at its expense will
                                 ---------
promptly compute such adjustment in accordance with the terms of this
Warrant and prepare a certificate setting forth such adjustment, including a
statement of the adjusted Exercise Price and adjusted number or type of
Warrant Shares or other securities issuable upon exercise of this Warrant
(as applicable), describing the transactions giving rise to such adjustments
and showing in detail the facts upon which such adjustment is based. Upon
written request, the Company will promptly deliver a copy of each such
certificate to the Holder and to the Company's transfer agent.

                  (h)      Notice of Corporate Events. If the Company
                           --------------------------
(i) declares a dividend or any other distribution of cash, securities or
other property in respect of its Common Stock, including without limitation
any granting of rights or warrants to subscribe for or purchase any capital
stock of the Company or any Subsidiary, (ii) authorizes or approves, enters
into any agreement contemplating or solicits shareholder approval for any
Fundamental Transaction or (iii) authorizes the voluntary dissolution,
liquidation or winding up of the affairs of the Company, then the Company
shall deliver to the Holder a notice describing the material terms and
conditions of such transaction, at least 20 calendar days prior to the
applicable record or effective date on which a Person would need to hold
Common Stock in order to participate in or vote with respect to such
transaction, and the Company will take all steps reasonably necessary in
order to insure that the Holder is given the practical opportunity to
exercise this Warrant prior to such time so as to participate in or vote
with respect to such transaction; provided, however, that the failure to
deliver such notice or any defect therein shall not affect the validity of
the corporate action required to be described in such notice.

                                    -7-

<PAGE>
<PAGE>

         10.      Payment of Exercise Price. The Holder may pay the Exercise
                  -------------------------
Price in one of the following manners:

                  (a)      Cash Exercise. The Holder may deliver immediately
                           -------------
available funds; or

                  (b)      Cashless Exercise. The Holder may notify the
                           -----------------
Company in an Exercise Notice of its election to utilize cashless exercise,
in which event the Company shall issue to the Holder the number of Warrant
Shares determined as follows:

                                    X = Y [(A-B)/A]

                           where:

                                    X = the number of Warrant Shares to be
                                    issued to the Holder.

                                    Y = the number of Warrant Shares with
                                    respect to which this Warrant is being
                                    exercised.

                                    A = the average of the closing prices
                                    for the five Trading Days immediately
                                    prior to (but not including) the
                                    Exercise Date.

                                    B = the Exercise Price.

For purposes of Rule 144 promulgated under the Securities Act, it is
intended, understood and acknowledged that the Warrant Shares issued in a
cashless exercise transaction shall be deemed to have been acquired by the
Holder, and the holding period for the Warrant Shares shall be deemed to
have commenced, on the date this Warrant was originally issued.

         11.      Limitations on Exercise.
                  -----------------------

                           (i)      Notwithstanding anything to the contrary
contained herein, the number of shares of Common Stock that may be acquired
by the Holder upon any exercise of this Warrant (or otherwise in respect
hereof) shall be limited to the extent necessary to insure that, following
such exercise (or other issuance), the total number of shares of Common
Stock then beneficially owned by such Holder and its Affiliates and any
other Persons whose beneficial ownership of Common Stock would be aggregated
with the Holder's for purposes of Section 13(d) of the Exchange Act, does
not exceed 9.999% of the total number of issued and outstanding shares of
Common Stock (including for such purpose the shares of Common Stock issuable
upon such exercise). For such purposes, beneficial ownership shall be
determined in accordance with Section 13(d) of the Exchange Act and the
rules and regulations promulgated thereunder. This provision shall not
restrict the number of shares of Common Stock which a Holder may receive or
beneficially own in order to determine the amount of securities or other
consideration that such Holder may receive in the event of a Fundamental
Transaction involving the Company as contemplated in Section 9 of this
Warrant. This restriction may not be waived.

                           (ii)     If the Company has not obtained the
Shareholder Approval (as defined below), then the Company may not issue in
excess of 3,261,467 shares of Common Stock upon exercise of the Warrants (as
defined in the Purchase Agreement) at an exercise price


                                    -8-

<PAGE>
<PAGE>

which is lower than the closing bid price of the Common Stock on the date of
issuance of this Warrant (such number of shares of Common Stock, the
"ISSUABLE MAXIMUM"). Each holder of Warrants shall be entitled to a portion
of the Issuable Maximum equal to the quotient obtained by dividing: (x) the
purchase price paid by it pursuant to the Purchase Agreement by (y) the
purchase price paid by all holders pursuant to the Purchase Agreement. If a
holder of Warrants shall no longer hold its Warrant due to exercise or
cancellation of its Warrant, then such holder's remaining portion of the
Issuable Maximum shall be allocated pro-rata among the remaining holders of
the Warrants. If on any Date of Exercise: (A) the aggregate number of shares
of Common Stock that would then be issuable upon exercise in full of this
Warrant would exceed the Issuable Maximum, and (B) the Company shall not
have previously obtained the vote of shareholders (the "SHAREHOLDER
APPROVAL"), if any, as may be required by the applicable rules and
regulations of the Nasdaq National Market (or any successor entity)
applicable to approve the issuance of shares of Common Stock in excess of
the Issuable Maximum pursuant to the terms hereof, then the Company shall
issue to the Holder a number of shares of Common Stock equal to the Issuable
Maximum and, with respect to the remainder of the Warrant Shares then
issuable under the Warrant for which an exercise in accordance with the
applicable exercise price would result in an issuance of shares of Common
Stock in excess of the Issuable Maximum (the "EXCESS WARRANT SHARES"), the
Holder shall have the option to require the Company to use its best efforts
to obtain the Shareholder Approval applicable to such issuance as soon as is
possible, but in any event not later than the 90th day after such request.
The Company and the Holder understand and agree that shares of Common Stock
issued to and then held by the Holder as a result of exercise of this
Warrant shall not be entitled to cast votes on any resolution to obtain
Shareholder Approval pursuant hereto. If the Company shall succeed in
obtaining the Shareholder Approval, the Excess Warrant Shares shall again
become fully exercisable by the Holder.

         12.      No Fractional Shares. No fractional shares of Warrant Shares
                  --------------------
will be issued in connection with any exercise of this Warrant. In lieu of
any fractional shares which would, otherwise be issuable, the Company shall
pay cash equal to the product of such fraction multiplied by the closing
price of one Warrant Share as reported by the applicable Trading Market on
the date of exercise.

         13.      Notices. Any and all notices or other communications or
                  -------
deliveries hereunder (including, without limitation, any Exercise Notice)
shall be in writing and shall be deemed given and effective on the earliest
of (i) the date of transmission, if such notice or communication is
delivered via facsimile at the facsimile number specified in this Section
prior to 6:30 p.m. (New York City time) on a Trading Day, (ii) the next
Trading Day after the date of transmission, if such notice or communication
is delivered via facsimile at the facsimile number specified in this Section
on a day that is not a Trading Day or later than 6:30 p.m. (New York City
time) on any Trading Day, (iii) the Trading Day following the date of
mailing, if sent by nationally recognized overnight courier service, or (iv)
upon actual receipt by the party to whom such notice is required to be
given. The addresses for such communications shall be: (i) if to the
Company, to Zoltek Companies, Inc., 3101 McKelvey Road, St. Louis, Missouri
63044, Attn: Chief Financial Officer, Facsimile No.: (314) 291-9082, or (ii)
if to the Holder, to the address or facsimile number appearing on the
Warrant Register or such other address or facsimile number as the Holder may
provide to the Company in accordance with this Section.

                                    -9-

<PAGE>
<PAGE>

         14.      Warrant Agent. The Company shall serve as warrant agent under
                  -------------
this Warrant. Upon 30 days' notice to the Holder, the Company may appoint a new
warrant agent. Any corporation into which the Company or any new warrant
agent may be merged or any corporation resulting from any consolidation to
which the Company or any new warrant agent shall be a party or any
corporation to which the Company or any new warrant agent transfers
substantially all of its corporate trust or shareholders services business
shall be a successor warrant agent under this Warrant without any further
act. Any such successor warrant agent shall promptly cause notice of its
succession as warrant agent to be mailed (by first class mail, postage
prepaid) to the Holder at the Holder's last address as shown on the Warrant
Register.

         15.      Miscellaneous.
                  -------------

                  (a)      This Warrant shall be binding on and inure to the
benefit of the parties hereto and their respective successors and assigns.
Subject to the preceding sentence, nothing in this Warrant shall be
construed to give to any Person other than the Company and the Holder any
legal or equitable right, remedy or cause of action under this Warrant. This
Warrant may be amended only in writing signed by the Company and the Holder
and their successors and assigns.

                  (b)      All questions concerning the construction, validity,
enforcement and interpretation of this Warrant shall be governed by and
construed and enforced in accordance with the internal laws of the State of
New York, without regard to the principles of conflicts of law thereof. Each
party agrees that all legal proceedings concerning the interpretations,
enforcement and defense of this Warrant and the transactions herein
contemplated ("PROCEEDINGS") (whether brought against a party hereto or its
respective Affiliates, employees or agents) shall be commenced exclusively
in the state and federal courts sitting in the City of New York, Borough of
Manhattan (the "NEW YORK COURTS"). Each party hereto hereby irrevocably
submits to the exclusive jurisdiction of the New York Courts for the
adjudication of any dispute hereunder or in connection herewith or with any
transaction contemplated hereby or discussed herein, and hereby irrevocably
waives, and agrees not to assert in any Proceeding, any claim that it is not
personally subject to the jurisdiction of any New York Court, or that such
Proceeding has been commenced in an improper or inconvenient forum. Each
party hereto hereby irrevocably waives personal service of process and
consents to process being served in any such Proceeding by mailing a copy
thereof via registered or certified mail or overnight delivery (with
evidence of delivery) to such party at the address in effect for notices to
it under this Warrant and agrees that such service shall constitute good and
sufficient service of process and notice thereof. Nothing contained herein
shall be deemed to limit in any way any right to serve process in any manner
permitted by law. Each party hereto hereby irrevocably waives, to the
fullest extent permitted by applicable law, any and all right to trial by
jury in any legal proceeding arising out of or relating to this Warrant or
the transactions contemplated hereby. If either party shall commence a
Proceeding to enforce any provisions of this Warrant, then the prevailing
party in such Proceeding shall be reimbursed by the other party for its
attorney's fees and other costs and expenses incurred with the
investigation, preparation and prosecution of such Proceeding.

                  (c)      The headings herein are for convenience only,
do not constitute a part of this Warrant and shall not be deemed to limit
or affect any of the provisions hereof.

                                    -10-

<PAGE>
<PAGE>

                  (d)      In case any one or more of the provisions of this
Warrant shall be invalid or unenforceable in any respect, the validity and
enforceability of the remaining terms and provisions of this Warrant shall
not in any way be affected or impaired thereby and the parties will attempt
in good faith to agree upon a valid and enforceable provision which shall be
a commercially reasonable substitute therefor, and upon so agreeing, shall
incorporate such substitute provision in this Warrant.

                [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK,
                           SIGNATURE PAGE FOLLOWS]


                                    -11-

<PAGE>
<PAGE>


         IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed by its authorized officer as of the date first indicated above.

                                    ZOLTEK COMPANIES, INC.

                                    By:
                                        -----------------------------------
                                    Name:
                                    Title:


                                    -12-

<PAGE>
<PAGE>

                               EXERCISE NOTICE

To [COMPANY]:

         The undersigned hereby irrevocably elects to purchase _____________
shares of common stock, par value $0.01 per share, of ZOLTEK COMPANIES INC.
("COMMON STOCK"), pursuant to Warrant No. [ ], originally issued January
[ ], 2004 (the "WARRANT"), and, if such Holder is not utilizing the cashless
exercise provisions set forth in the Warrant, encloses herewith $________ in
cash, certified or official bank check or checks or other immediately
available funds, which sum represents the aggregate Exercise Price (as
defined in the Warrant) for the number of shares of Common Stock to which
this Exercise Notice relates, together with any applicable taxes payable by
the undersigned pursuant to the Warrant.

         By its delivery of this Exercise Notice, the undersigned represents
and warrants to the Company that in giving effect to the exercise evidenced
hereby the Holder will not beneficially own in excess of the number of
shares of Common Stock (determined in accordance with Section 13(d) of the
Securities Exchange Act of 1934) permitted to be owned under Section 11 of
this Warrant to which this notice relates.

         The undersigned requests that certificates for the shares of Common
Stock issuable upon this exercise be issued in the name of

                                           PLEASE INSERT SOCIAL SECURITY OR
                                           TAX IDENTIFICATION NUMBER


                       (Please print name and address)


                                    -13-

<PAGE>
<PAGE>

                         Warrant Shares Exercise Log
                         ---------------------------

------------------------------------------------------------------------------
                 Number of                              Number of
                 Warrant Shares      Number of          Warrant Shares
                 Available to be     Warrant Shares     Remaining to
Date             Exercised           Exercised          be Exercised
------------------------------------------------------------------------------














------------------------------------------------------------------------------



<PAGE>
<PAGE>


                             FORM OF ASSIGNMENT

         [To be completed and signed only upon transfer of Warrant]

         FOR VALUE RECEIVED, the undersigned hereby sells, assigns and
transfers unto                                  the right represented by the
               --------------------------------
within Warrant to purchase              shares of Common Stock of ZOLTEK
                           ------------
COMPANIES INC. to which the within Warrant relates and appoints
                 attorney to transfer said right on the books of the Company
----------------
with full power of substitution in the premises.

Dated:                  ,
      ------------------  ----


                            ---------------------------------------
                            (Signature must conform in all respects
                            to name of holder as specified on the
                            face of the Warrant)



                            ---------------------------------------
                            Address of Transferee



                            ---------------------------------------

                            ---------------------------------------


In the presence of:



--------------------------