Delivery other than in the manner or to the address listed below will not constitute valid delivery.

FORM 1-EXERCISE OF SUBSCRIPTION RIGHTS

To subscribe for shares pursuant to your Basic Subscription Right, please complete lines (a) and (c) and sign under Form 3 below. To subscribe for shares pursuant to your Over-Subscription Right, please also complete line (b) and sign under Form 3 below. To the extent your investment exceeds Shares that you are entitled under either the Basic Subscription Right or the Over-Subscription Right, you will be deemed to have elected to purchase the maximum number of shares for which you are entitled to subscribe under the Basic Subscription Right or Over-Subscription Right, as applicable.

(a) EXERCISE OF BASIC SUBSCRIPTION RIGHT:

I exercise ______________ rights x $ 0.65	= $_______________
(no. of subscription rights)	(amount enclosed)

(b) EXERCISE OF OVER-SUBSCRIPTION RIGHT

If you have exercised your Basic Subscription Right in full and wish to subscribe for additional shares pursuant to your Over-Subscription Right:

I apply to invest an additional $_________ (enclosed) towards additional Shares of Common Stock pursuant to my over-subscription privilege.

METHOD OF PAYMENT (CHECK ONE)

¨	Check or bank draft payable to “American Stock Transfer & Trust Company, LLC as Subscription Agent.”

Wire transfer of immediately available funds directly to the account maintained by American Stock Transfer & Trust Company, LLC, as Subscription Agent, for purposes of accepting subscriptions in this Rights Offering at JPMorgan Chase Bank, 55 Water Street, New York, New York 10005, ABA #021000021, Account # 530-354616 American Stock Transfer FBO SIGA Technologies, Inc., with reference to the rights holder's name.

FORM 2-DELIVERY TO DIFFERENT ADDRESS

If you wish for the Common Stock underlying your subscription rights, a certificate representing unexercised subscription rights or the proceeds of any sale of subscription rights to be delivered to an address different from that shown on the face of this Subscription Rights Certificate,

please enter the alternate address below, sign under Form 3 and have your signature guaranteed under Form 4.

FORM 3-SIGNATURE

TO SUBSCRIBE: I acknowledge that I have received the Prospectus for this Rights Offering and I hereby irrevocably exercise the number of Subscription Rights indicated above on the terms and conditions specified in the Prospectus. By signing below I confirm that (1) after giving effect to the exercise of my Rights, I will not beneficially own, as determined in accordance with Rule 13d-3 under the Securities Exchange Act of 1934, as amended, more than 14.99% of the Company’s outstanding shares of Common Stock (calculated immediately upon the closing of the rights offering after giving effect to the backstop agreement, as described in the Prospectus) and (2), if I already beneficially own, as determined in accordance with Rule 13d-3 under the Securities Exchange Act of 1934, as amended, in excess of 14.99% of the Company’s outstanding shares of Common Stock I will not, via the exercise of the Rights, increase my proportionate interest in the Company’s Common Stock (with respect to (1) or (2), any such excess shares, the “Excess Shares”). With respect to any such Excess Shares, I hereby (1) irrevocably appoint and constitute the Company, each of its authorized officers and their designees, and each of them, with full power of substitution, as my proxy and attorney in fact with full authority to vote and act by written consent with respect to any such Excess Shares on any matter submitted to shareholders for a vote or action by written consent, in the discretion of such proxy, to the same extent I would have the power to vote or act by written consent and (2) grant the Company a right for 90 days from the closing of the rights offering to repurchase such Excess Shares at the lesser of $1.50 per share or 85% of the closing volume weighted average price per share of our common stock as reported on the OTC Pink Sheets on [●], 2016, subject to the Company’s extension or earlier termination (the “Expiration Date”). I agree to cooperate with the Company and provide to the Company any and all information requested by the Company in connection with the exercise of the rights granted in the previous sentence. The undersigned acknowledges that the number of shares that the undersigned may obtain by subscribing for shares in this offering cannot be determined on the date subscription rights are exercised hereby, but that the undersigned will obtain the number of shares equal to the result of dividing the accepted dollar amount of investment by the Subscription Price on the Expiration Date.

Signature(s):

IMPORTANT: The signature(s) must correspond with the name(s) as printed on the reverse of this Subscription Rights Certificate in every particular, without alteration or enlargement, or any other change whatsoever.

FORM 4-SIGNATURE GUARANTEE

This form must be completed if you have completed any portion of Form 2.

Signature Guaranteed:
		(Name of Bank or Firm)

By:
		(Signature of Officer)

IMPORTANT: The signature(s) should be guaranteed by an eligible guarantor institution (bank, stock broker, savings & loan association or credit union) with membership in an approved signature guarantee medallion program pursuant to Securities and Exchange Commission Rule 17Ad-15.

FOR INSTRUCTIONS ON THE USE OF SIGA TECHNOLOGIES, INC. SUBSCRIPTION RIGHTS CERTIFICATES, CONSULT D.F. KING & CO., INC., THE INFORMATION AGENT, TOLL FREE AT (800) 207-2872 OR BY EMAIL AT INFOAGENT@DFKING.COM.