<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>013 - Disclosure - Cost-Method Investment</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

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</LabelSeparator><Level>2</Level><ElementName>us-gaap_CostAndEquityMethodInvestmentsDisclosureTextBlock</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole>verboseLabel</PreferredLabelRole><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="Context_6ME__30-Jun-2013" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;div align="justify" style="text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt; font-weight: bold;"&gt;6. Cost-Method Investment&lt;/font&gt;&lt;/div&gt;
&lt;div align="justify" style="text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;
&lt;div align="justify" style="text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;On January 31, 2013, the Company entered into a subscription agreement with Darrell Lerner and DCL Ventures, Inc. (&amp;#8220;DCL&amp;#8221;) in connection with Mr. Lerner&amp;#8217;s separation from the Company.&amp;#160;&amp;#160;Pursuant to this agreement, the Company made an initial investment in DCL by purchasing 50,000 shares of DCL&amp;#8217;s common stock, $0.001 par value per share, for an aggregate purchase price of $50,000 in April 2013.&amp;#160;&amp;#160;These nonmarketable securities have been included in the Company&amp;#8217;s Consolidated Balance Sheet measured on a cost basis (See Note 16).&lt;/font&gt;&lt;/font&gt;&lt;/div&gt;
&lt;div align="justify" style="text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;
&lt;div align="justify" style="text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;"&gt;
&lt;div align="justify" style="text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;&lt;font style="display: inline; font-family: times new roman; font-size: 10pt;"&gt;As of June 30, 2013, the aggregate carrying amount of the Company&amp;#8217;s cost-method investment in a noncontrolled entity was $50,000, and was recorded in Investments on the Company&amp;#8217;s Consolidated Balance Sheets.&amp;#160;&amp;#160;The Company assesses all cost-method investments for impairment quarterly.&amp;#160;&amp;#160;No impairment loss was recorded during the three and six months ended June 30, 2013.&amp;#160;&amp;#160;The Company does not reassess the fair value of cost-method investments if there are no identified events or changes in circumstances that may have a significant adverse effect on the fair value of the investments (See Note 16).&lt;/font&gt;&lt;/font&gt;&lt;/font&gt;&lt;/div&gt;
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