<SEC-DOCUMENT>0001140361-15-023287.txt : 20150604
<SEC-HEADER>0001140361-15-023287.hdr.sgml : 20150604
<ACCEPTANCE-DATETIME>20150604184744
ACCESSION NUMBER:		0001140361-15-023287
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20150602
FILED AS OF DATE:		20150604
DATE AS OF CHANGE:		20150604

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SIGA TECHNOLOGIES INC
		CENTRAL INDEX KEY:			0001010086
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				133864870
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		660 MADISON AVENUE
		STREET 2:		SUITE 1700
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10065
		BUSINESS PHONE:		212-672-9100

	MAIL ADDRESS:	
		STREET 1:		660 MADISON AVENUE
		STREET 2:		SUITE 1700
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10065

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SIGA PHARMACEUTICALS INC
		DATE OF NAME CHANGE:	19961108

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ROSE ERIC A MD
		CENTRAL INDEX KEY:			0001139301

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23047
		FILM NUMBER:		15914090

	MAIL ADDRESS:	
		STREET 1:		161 FORT WASHINGTON AVENUE
		STREET 2:		7TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10032
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-06-02</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001010086</issuerCik>
        <issuerName>SIGA TECHNOLOGIES INC</issuerName>
        <issuerTradingSymbol>SIGAQ</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001139301</rptOwnerCik>
            <rptOwnerName>ROSE ERIC A MD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SIGA TECHNOLOGIES, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>660 MADISON AVENUE, SUITE 1700</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10065</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $.0001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2015-06-02</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.80</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>472797</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $.0001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2015-06-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>12500</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.69</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>460297</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $.0001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2015-06-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>12400</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.64</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>447897</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The Reporting Person is obligated to fund certain tax withholding obligations of SIGA Technologies, Inc. (the &quot;Issuer&quot;) arising from the expected receipt of shares of Common Stock of the Issuer by the Reporting Person in connection with the vesting of restricted stock units and the subsequent delivery of shares of Common Stock in connection therewith.  This Form 4 reports the sale by the Reporting Person of 25,000 shares of Common Stock, which shares of Common Stock were sold to raise the funds required to satisfy such withholding tax obligations.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Eric A. Rose</signatureName>
        <signatureDate>2015-06-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
