<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-08-23</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001492691</issuerCik>
        <issuerName>Knight-Swift Transportation Holdings Inc.</issuerName>
        <issuerTradingSymbol>KNX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000901736</rptOwnerCik>
            <rptOwnerName>MOYES JERRY</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2200 S. 75TH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PHOENIX</rptOwnerCity>
            <rptOwnerState>AZ</rptOwnerState>
            <rptOwnerZipCode>85043</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of 10% group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001272829</rptOwnerCik>
            <rptOwnerName>MOYES VICKIE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P.O. BOX 1397</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>TOLLESON</rptOwnerCity>
            <rptOwnerState>AZ</rptOwnerState>
            <rptOwnerZipCode>85353</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001092565</rptOwnerCik>
            <rptOwnerName>MOYES JERRY &amp; VICKIE FAMILY TRUST</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2200 S. 75TH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PHOENIX</rptOwnerCity>
            <rptOwnerState>AZ</rptOwnerState>
            <rptOwnerZipCode>85043</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Forward Sale Contract (obligation to sell)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
                <footnoteId id="F7"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-08-23</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
                <footnoteId id="F7"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
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                <footnoteId id="F7"/>
            </exerciseDate>
            <expirationDate>
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                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
                <footnoteId id="F7"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8851692</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F8"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Manager and Member</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Forward Sale Contract (obligation to sell)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
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                <footnoteId id="F6"/>
                <footnoteId id="F7"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-08-23</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
                <footnoteId id="F7"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
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            </exerciseDate>
            <expirationDate>
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                <footnoteId id="F3"/>
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                <footnoteId id="F5"/>
                <footnoteId id="F6"/>
                <footnoteId id="F7"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8851692</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F8"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Manager and Member</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Forward Sale Contract (obligation to sell)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F7"/>
                <footnoteId id="F9"/>
                <footnoteId id="F10"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-08-23</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F7"/>
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            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                </transactionShares>
                <transactionPricePerShare>
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                    <footnoteId id="F2"/>
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                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
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            <expirationDate>
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            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9864000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F8"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Manager and Member</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Forward Sale Contract (obligation to sell)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
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            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-08-23</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
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            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                </transactionShares>
                <transactionPricePerShare>
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                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
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            <exerciseDate>
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            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9864000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
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                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Manager and Member</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Forward Sale Contract (obligation to sell)</value>
            </securityTitle>
            <conversionOrExercisePrice>
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            <transactionDate>
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            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
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                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
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            <ownershipNature>
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                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Manager and Member</value>
                </natureOfOwnership>
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            <securityTitle>
                <value>Forward Sale Contract (obligation to sell)</value>
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                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
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                </underlyingSecurityShares>
            </underlyingSecurity>
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                <footnoteId id="F7"/>
                <footnoteId id="F13"/>
                <footnoteId id="F14"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F7"/>
                <footnoteId id="F13"/>
                <footnoteId id="F14"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2376000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F12"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Manager and Member</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Forward Sale Contract (obligation to sell)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F7"/>
                <footnoteId id="F15"/>
                <footnoteId id="F16"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-08-23</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F7"/>
                <footnoteId id="F15"/>
                <footnoteId id="F16"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F15"/>
                    <footnoteId id="F16"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F7"/>
                <footnoteId id="F15"/>
                <footnoteId id="F16"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F7"/>
                <footnoteId id="F15"/>
                <footnoteId id="F16"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3331003</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F12"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Manager and Member</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Forward Sale Contract (obligation to sell)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F7"/>
                <footnoteId id="F15"/>
                <footnoteId id="F16"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-08-23</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F7"/>
                <footnoteId id="F15"/>
                <footnoteId id="F16"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F15"/>
                    <footnoteId id="F16"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F7"/>
                <footnoteId id="F15"/>
                <footnoteId id="F16"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
                <footnoteId id="F7"/>
                <footnoteId id="F15"/>
                <footnoteId id="F16"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3331003</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F12"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Manager and Member</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On August 23, 2019, Cactus Holding Company, LLC (&quot;Cactus I&quot;) and M Capital Group Investors II, LLC (&quot;M Capital II&quot;) entered into and amended certain prepaid variable share forward contracts (each a &quot;VPF&quot; and, collectively, the &quot;VPFs&quot;), as further described herein.</footnote>
        <footnote id="F2">Under the VPFs, Cactus I or M Capital II, as applicable, is obligated to deliver a variable amount of Class A Common Stock, par value $0.01 per share, of Knight-Swift Transportation Holdings Inc. (&quot;Class A Common Stock&quot;), or an equivalent amount of cash, upon certain dates set forth in the VPFs. The number of shares deliverable under the VPFs depends on the &quot;Forward Floor Price,&quot; &quot;Forward Cap Price,&quot; &quot;Number of Shares,&quot; and &quot;Settlement Price,&quot; each as defined in the applicable VPFs. The VPFs have one or more components, each with its own &quot;Valuation Date&quot; and &quot;Number of Shares.&quot;</footnote>
        <footnote id="F3">The actual number of shares required to be delivered under each component of the VPFs depends on the Settlement Price with respect to such component. If the Settlement Price is less than or equal to the Forward Floor Price on the relevant Valuation Date, the Number of Shares attributable to that component must be delivered. If the Settlement Price is greater than the Forward Floor Price but less than or equal to the Forward Cap Price, the number of shares to be delivered equals the Forward Floor Price, divided by the Settlement Price, multiplied by the Number of Shares. If the Settlement Price is greater than the Forward Cap Price, the number of shares to be delivered is equal to the product of (i) the Number of Shares and (ii) a fraction (a) the numerator of which is the sum of (x) the Forward Floor Price and (y) the Settlement Price minus the Forward Cap Price, and (b) the denominator of which is the Settlement Price.</footnote>
        <footnote id="F4">The Settlement Price under the VPFs is defined as the volume-weighted average price per share of Class A Common Stock on the New York Stock Exchange on the relevant &quot;Valuation Date&quot; (as defined in each component). The shares or cash deliverable generally must be delivered on the date that is one Settlement Cycle (as defined in 2002 ISDA Equity Derivatives Definitions) following the relevant Valuation Date.</footnote>
        <footnote id="F5">The reported transactions involve an amendment to an existing and previously reported VPF by M Capital II. The number of components remained unchanged at twenty. The Number of Shares underlying each component remained unchanged at 442,584 for eight of the components and 442,585 for 12 of the components. The amendment amended the Valuation Dates from August 30, 2019 through September 27, 2019 to March 13, 2020 through April 9, 2020. The maximum number of shares to be delivered under this VPF remained unchanged at 8,851,692.</footnote>
        <footnote id="F6">The Forward Floor Price and Forward Cap Price under this VPF changed from $40.9682 and $49.1983 to $44.50 and $56.50, respectively.</footnote>
        <footnote id="F7">In connection with the VPF transactions, M Capital II and Cactus I entered into a Trigger Price Agreement, pursuant to which M Capital II and Cactus I are obligated to make certain payments if the daily volume weighted average price of the Class A Common Stock equals or exceeds a &quot;Reset Trigger Price&quot; and the VPFs can be terminated if the daily volume weighted average price of the Class A Common Stock equals or exceeds an &quot;Early Termination Price.&quot;  Payments made under this agreement increase the Reset Trigger Price and Early Termination Price.  The initial Reset Trigger Price is $36.75 and the initial Early Termination Price is $39.70.  The amount of the required payments are determined by the counterparty in a commercially reasonable manner and using a consistent methodology as was used in determining the illustrative amounts provided to M Capital II and Cactus I prior to entering into the Trigger Price Agreement.</footnote>
        <footnote id="F8">Shares are held directly by M Capital II. The reporting persons constitute certain of the members of M Capital II. The reporting persons disclaim any beneficial ownership of these shares except to the extent of their pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of these shares for Section 16 or for any other purpose. The Jerry and Vickie Moyes Family Trust (the &quot;JVMF Trust&quot;) is the sole manager of M Capital II.</footnote>
        <footnote id="F9">The reported transactions involve the termination of an existing and previously reported VPF by M Capital II and the entry into a new VPF by M Capital II.  The number of components in the new VPF remained unchanged at twenty. The Number of Shares underlying each component remained unchanged at 493,200. The Valuation Dates under the previous VPF were August 30, 2019 through September 27, 2019 and the Valuation Dates under the new VPF are May 26, 2020 through June 22, 2020. The maximum number of shares to be delivered under the new VPF remained unchanged at 9,864,000.  M Capital  II was entitled to receive $313,966,000 in connection with the new VPF, which was applied in partial satisfaction of the $332,568,000 required to terminate the existing VPF.  The remaining $18,602,000 of the required termination payment was funded with a payment made by the counterparty for the benefit of M Capital II under the Trigger Price Agreement.</footnote>
        <footnote id="F10">The Forward Floor Price and Forward Cap Price under the previous VPF were $39.9687 and $47.9451, respectively.  The Forward Floor Price and Forward Cap Price under the new VPF are $42.50 and $52.95, respectively.</footnote>
        <footnote id="F11">The reported transactions involve an amendment to an existing and previously reported VPF by Cactus I. The number of components remained unchanged at three. The Number of Shares underlying each component remained unchanged at 1,681,436. The amendment amended the Valuation Dates from August 30, 2019 through September 4, 2019 to March 13, 2020 through March 17, 2020. The maximum number of shares to be delivered under this VPF remained unchanged at 5,044,308.</footnote>
        <footnote id="F12">Shares are held directly by Cactus I. Cactus I is a wholly owned subsidiary of Cactus Holding Company III, LLC (&quot;Cactus III&quot;), of which the reporting persons constitute all of the members. The JVMF Trust is the sole manager of Cactus I and Cactus III.</footnote>
        <footnote id="F13">The reported transactions involve an amendment to an existing and previously reported VPF by Cactus I. The number of components remained unchanged at three. The Number of Shares underlying each component remained unchanged at 792,000. The amendment amended the Valuation Dates from August 30, 2019 through September 4, 2019 to May 26, 2020 through May 28, 2020. The maximum number of shares to be delivered under this VPF remained unchanged at 2,376,000.</footnote>
        <footnote id="F14">The Forward Floor Price and Forward Cap Price under this VPF changed from $39.9687 and $47.9451 to $42.50 and $52.95, respectively.</footnote>
        <footnote id="F15">The reported transactions involve an amendment to an existing and previously reported VPF by Cactus I. The number of components remained unchanged at three. The Number of Shares underlying each component remained unchanged at 1,110,334 for two of the components and 1,110,335 for the third component. The amendment amended the Valuation Dates from August 30, 2019 through September 4, 2019 to May 26, 2020 through May 28, 2020. The maximum number of shares to be delivered under this VPF remained unchanged at 3,331,003.</footnote>
        <footnote id="F16">The Forward Floor Price and Forward Cap Price under this VPF changed from $35.9841 and $42.9762 to $42.00 and $52.25, respectively.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Jerry Moyes, by Earl Scudder, attorney-in-fact, pursuant to a POA previously filed</signatureName>
        <signatureDate>2019-08-27</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Vickie Moyes, by Earl Scudder, attorney-in-fact, pursuant to a POA previously filed</signatureName>
        <signatureDate>2019-08-27</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Jerry Moyes, Co-Trustee of the Jerry and Vickie Moyes Family Trust, by Earl Scudder, attorney-in-fact, pursuant to a POA previously filed</signatureName>
        <signatureDate>2019-08-27</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Vickie Moyes, Co-Trustee of the Jerry and Vickie Moyes Family Trust, by Earl Scudder, attorney-in-fact, pursuant to a POA previously filed</signatureName>
        <signatureDate>2019-08-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
