<?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>010920 - Disclosure - Retained Interests In Securitizations</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>1</Level><ElementName>bmnm_RetainedInterestsInSecuritizationsAbstract</ElementName><ElementPrefix>bmnm_</ElementPrefix><IsBaseElement>false</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><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Retained Interests In Securitizations [Abstract]</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>bmnm_RetainedInterestsInSecuritizationsTextBlock</ElementName><ElementPrefix>bmnm_</ElementPrefix><IsBaseElement>false</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="FROM_Jan01_2013_TO_Jun30_2013" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;p style='margin-top:0pt; margin-bottom:0pt'&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;font-weight:bold;margin-left:0px;"&gt;NOTE 3&lt;/font&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;font-weight:bold;"&gt;.&lt;/font&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;font-weight:bold;"&gt;  RETAINED INTERESTS&lt;/font&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;font-weight:bold;"&gt; IN SECURITIZATIONS&lt;/font&gt;&lt;/p&gt;&lt;p style='margin-top:0pt; margin-bottom:0pt'&gt;&amp;#160;&lt;/p&gt;&lt;p style='margin-top:0pt; margin-bottom:0pt'&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;margin-left:18px;"&gt;The following table summarizes the &lt;/font&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;"&gt;estimated fair value of the &lt;/font&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;"&gt;Company's re&lt;/font&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;"&gt;tained &lt;/font&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;"&gt;interests in asset backed securities as of &lt;/font&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;"&gt;June 30, 2013&lt;/font&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;"&gt;December 31, &lt;/font&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;"&gt;2012&lt;/font&gt;&lt;font style="font-family:Arial Narrow;font-size:11pt;"&gt;:&lt;/font&gt;&lt;/p&gt;&lt;div style="text-align:center;"&gt;&amp;#160;&lt;/div&gt;&lt;p style='margin-top: 0pt; margin-bottom: 0pt;'&gt;&lt;/p&gt;&lt;div&gt;&lt;table style="border-collapse:collapse;margin-top:20px;"&gt;&lt;tr style="height: 17px"&gt;&lt;td   style="width: 155px; border-bottom-style:solid;border-bottom-width:2px;text-align:left;border-color:#000000;min-width:155px;"&gt;&lt;font style="FONT-STYLE: italic;FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;(in thousands)&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 315px; border-bottom-style:solid;border-bottom-width:2px;text-align:left;border-color:#000000;min-width:315px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 10px; border-bottom-style:solid;border-bottom-width:2px;text-align:left;border-color:#000000;min-width:10px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 115px; border-bottom-style:solid;border-bottom-width:2px;text-align:left;border-color:#000000;min-width:115px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 10px; border-bottom-style:solid;border-bottom-width:2px;text-align:left;border-color:#000000;min-width:10px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 115px; border-bottom-style:solid;border-bottom-width:2px;text-align:left;border-color:#000000;min-width:115px;"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;&lt;tr style="height: 17px"&gt;&lt;td   style="width: 155px; border-top-style:solid;border-top-width:2px;border-bottom-style:solid;border-bottom-width:1px;text-align:left;border-color:#000000;min-width:155px;"&gt;&lt;font style="FONT-WEIGHT: bold;FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;TEXT-ALIGN: left;"&gt;Series&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 315px; border-top-style:solid;border-top-width:2px;border-bottom-style:solid;border-bottom-width:1px;text-align:left;border-color:#000000;min-width:315px;"&gt;&lt;font style="FONT-WEIGHT: bold;FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;TEXT-ALIGN: left;"&gt;Issue Date&lt;/font&gt;&lt;/td&gt;&lt;td colspan="2"  style="width: 125px; border-top-style:solid;border-top-width:2px;border-bottom-style:solid;border-bottom-width:1px;text-align:center;border-color:#000000;min-width:125px;"&gt;&lt;font style="FONT-WEIGHT: bold;FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;TEXT-ALIGN: center;"&gt;June 30, 2013&lt;/font&gt;&lt;/td&gt;&lt;td colspan="2"  style="width: 125px; border-top-style:solid;border-top-width:2px;border-bottom-style:solid;border-bottom-width:1px;text-align:center;border-color:#000000;min-width:125px;"&gt;&lt;font style="FONT-WEIGHT: bold;FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;TEXT-ALIGN: center;"&gt;December 31, 2012&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr style="height: 17px"&gt;&lt;td   style="width: 155px; border-top-style:solid;border-top-width:1px;text-align:left;border-color:#000000;min-width:155px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;HMAC 2004-1&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 315px; border-top-style:solid;border-top-width:1px;text-align:left;border-color:#000000;min-width:315px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;March 4, 2004&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 10px; border-top-style:solid;border-top-width:1px;text-align:left;border-color:#000000;min-width:10px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;$&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 115px; border-top-style:solid;border-top-width:1px;text-align:right;border-color:#000000;min-width:115px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt; 40&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 10px; border-top-style:solid;border-top-width:1px;text-align:left;border-color:#000000;min-width:10px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;$&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 115px; border-top-style:solid;border-top-width:1px;text-align:right;border-color:#000000;min-width:115px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt; 74&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr style="height: 17px"&gt;&lt;td   style="width: 155px; text-align:left;border-color:#000000;min-width:155px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;HMAC 2004-2&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 315px; text-align:left;border-color:#000000;min-width:315px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;May 10, 2004&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 10px; text-align:left;border-color:#000000;min-width:10px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 115px; text-align:right;border-color:#000000;min-width:115px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt; -&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 10px; text-align:left;border-color:#000000;min-width:10px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 115px; text-align:right;border-color:#000000;min-width:115px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt; 890&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr style="height: 17px"&gt;&lt;td   style="width: 155px; text-align:left;border-color:#000000;min-width:155px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;HMAC 2004-3&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 315px; text-align:left;border-color:#000000;min-width:315px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;June 30, 2004&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 10px; text-align:left;border-color:#000000;min-width:10px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 115px; text-align:right;border-color:#000000;min-width:115px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt; 1,563&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 10px; text-align:left;border-color:#000000;min-width:10px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 115px; text-align:right;border-color:#000000;min-width:115px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt; 750&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr style="height: 17px"&gt;&lt;td   style="width: 155px; text-align:left;border-color:#000000;min-width:155px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;HMAC 2004-4&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 315px; text-align:left;border-color:#000000;min-width:315px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;August 16, 2004&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 10px; text-align:left;border-color:#000000;min-width:10px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 115px; text-align:right;border-color:#000000;min-width:115px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt; 1,380&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 10px; text-align:left;border-color:#000000;min-width:10px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 115px; text-align:right;border-color:#000000;min-width:115px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt; 881&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr style="height: 17px"&gt;&lt;td   style="width: 155px; text-align:left;border-color:#000000;min-width:155px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;HMAC 2004-5&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 315px; text-align:left;border-color:#000000;min-width:315px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;September 28, 2004&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 10px; text-align:left;border-color:#000000;min-width:10px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 115px; text-align:right;border-color:#000000;min-width:115px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt; 480&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 10px; text-align:left;border-color:#000000;min-width:10px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 115px; text-align:right;border-color:#000000;min-width:115px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt; 741&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr style="height: 17px"&gt;&lt;td   style="width: 155px; border-top-style:solid;border-top-width:1px;border-bottom-style:double;border-bottom-width:3px;text-align:left;border-color:#000000;min-width:155px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;              Total&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 315px; border-top-style:solid;border-top-width:1px;border-bottom-style:double;border-bottom-width:3px;text-align:left;border-color:#000000;min-width:315px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 10px; border-top-style:solid;border-top-width:1px;border-bottom-style:double;border-bottom-width:3px;text-align:left;border-color:#000000;min-width:10px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;$&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 115px; border-top-style:solid;border-top-width:1px;border-bottom-style:double;border-bottom-width:3px;text-align:right;border-color:#000000;min-width:115px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt; 3,463&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 10px; border-top-style:solid;border-top-width:1px;border-bottom-style:double;border-bottom-width:3px;text-align:left;border-color:#000000;min-width:10px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt;$&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 115px; border-top-style:solid;border-top-width:1px;border-bottom-style:double;border-bottom-width:3px;text-align:right;border-color:#000000;min-width:115px;"&gt;&lt;font style="FONT-FAMILY: Arial Narrow;FONT-SIZE: 10pt;COLOR: #000000;"&gt; 3,336&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>No authoritative reference available.</ElementDefenition><ElementReferences>No definition available.</ElementReferences><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Retained Interests In Securitizations</Label></Row></Rows><Footnotes /><IsEquityReport>false</IsEquityReport><ReportName>Retained Interests In Securitizations</ReportName><MonetaryRoundingLevel>UnKnown</MonetaryRoundingLevel><SharesRoundingLevel>UnKnown</SharesRoundingLevel><PerShareRoundingLevel>UnKnown</PerShareRoundingLevel><ExchangeRateRoundingLevel>UnKnown</ExchangeRateRoundingLevel><HasCustomUnits>true</HasCustomUnits><IsEmbedReport>false</IsEmbedReport><IsMultiCurrency>false</IsMultiCurrency><ReportType>Sheet</ReportType><RoleURI>http://www.biminicapital.com/role/DisclosureRetainedInterestsInSecuritizations</RoleURI><NumberOfCols>1</NumberOfCols><NumberOfRows>2</NumberOfRows></InstanceReport>
