<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><Version>2.2.0.25</Version><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><ReportLongName>11001 - Disclosure - Net loss per common unitholders' interest</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelColumn>false</LabelColumn><CurrencyCode>USD</CurrencyCode><FootnoteIndexer /><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><MCU><KeyName>8/1/2010 - 10/31/2010
USD ($)

USD ($) / shares
</KeyName><CurrencySymbol>$</CurrencySymbol><contextRef><ContextID>Duration_8_1_2010_To_10_31_2010</ContextID><EntitySchema>http://www.sec.gov/CIK</EntitySchema><EntityValue>0000922358</EntityValue><PeriodDisplayName /><PeriodType>duration</PeriodType><PeriodStartDate>2010-08-01T00:00:00</PeriodStartDate><PeriodEndDate>2010-10-31T00:00:00</PeriodEndDate><Segments /><Scenarios /></contextRef><UPS><UnitProperty><UnitID>Unit12</UnitID><UnitType>Standard</UnitType><StandardMeasure><MeasureSchema>http://www.xbrl.org/2003/iso4217</MeasureSchema><MeasureValue>USD</MeasureValue><MeasureNamespace>iso4217</MeasureNamespace></StandardMeasure><Scale>0</Scale></UnitProperty><UnitProperty><UnitID>Unit13</UnitID><UnitType>Divide</UnitType><NumeratorMeasure><MeasureSchema>http://www.xbrl.org/2003/iso4217</MeasureSchema><MeasureValue>USD</MeasureValue><MeasureNamespace>iso4217</MeasureNamespace></NumeratorMeasure><DenominatorMeasure><MeasureSchema>http://www.xbrl.org/2003/instance</MeasureSchema><MeasureValue>shares</MeasureValue><MeasureNamespace>xbrli</MeasureNamespace></DenominatorMeasure><Scale>0</Scale></UnitProperty></UPS><CurrencyCode>USD</CurrencyCode><OriginalCurrencyCode>USD</OriginalCurrencyCode></MCU><CurrencySymbol>$</CurrencySymbol><Labels><Label Id="1" Label="3 Months Ended" /><Label Id="2" Label="Oct. 31, 2010" /></Labels></Column></Columns><Rows><Row><Id>5</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><Level>0</Level><ElementName>us-gaap_EarningsPerShareTextBlock</ElementName><ElementPrefix>us-gaap</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><ShortDefinition>No definition available.</ShortDefinition><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsSubReportEnd>false</IsSubReportEnd><IsCalendarTitle>false</IsCalendarTitle><IsTuple>false</IsTuple><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole>terselabel</PreferredLabelRole><FootnoteIndexer /><Cells><Cell><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;div&gt;
&lt;div style="font-family: Times New Roman;"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&lt;b&gt;&lt;font style="font-size: 10pt; font-weight: bold;" class="_mt" size="2"&gt;J.&lt;/font&gt;&lt;/b&gt;&lt;b&gt;&lt;font style="font-size: 3pt; font-weight: bold;" class="_mt" size="1"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; &lt;/font&gt;&lt;/b&gt;&lt;b&gt;&lt;font style="font-size: 10pt; font-weight: bold;" class="_mt" size="2"&gt;Net loss per common unitholders' interest&lt;/font&gt;&lt;/b&gt;&lt;/p&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt; &lt;/font&gt;&amp;nbsp;&lt;/p&gt;
&lt;p style="margin: 0in 0in 0pt 0.25in;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;Below is a calculation of the basic and diluted net loss per common unitholders' interest in the condensed consolidated statements of earnings for the periods indicated. In accordance with guidance issued by the FASB regarding participating securities and the two-class method, Ferrellgas calculates net earnings per common unitholders' interest for each period presented according to distributions declared and participation rights in undistributed earnings, as if all of the earnings for the period had been distributed. In periods with undistributed earnings above certain levels, the calculation according to the two-class method results in an increased allocation of undistributed earnings to the general partner and a dilution of the earnings to the limited partners. Due to the seasonality of the propane business, the dilution effect of the guidance on the two-class method typically impacts only the three months ending January&amp;nbsp;31. There was not a dilutive effect resulting from this guidance on basic and diluted net loss per common unitholders' interest for the three months ended October&amp;nbsp;31, 2010 and 2009.&lt;/font&gt;&lt;/p&gt;
&lt;p style="margin: 0in 0in 0pt 0.25in;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt; &lt;/font&gt;&amp;nbsp;&lt;/p&gt;
&lt;p style="margin: 0in 0in 0pt 0.25in;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;In periods with year-to-date net losses, the allocation of the net losses to the limited partners and the general partner will be determined based on the same allocation basis specified in the Ferrellgas Partners' partnership agreement that would apply to periods in which there were no undistributed earnings. Ferrellgas typically incurs net losses in the three month period ended October&amp;nbsp;31.&lt;/font&gt;&lt;/p&gt;
&lt;p style="text-align: center; margin: 0in 0in 0pt;" align="center"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt; &lt;/font&gt;&amp;nbsp;&lt;/p&gt;
&lt;p style="text-align: center; margin: 0in 0in 0pt;" align="center"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt; &lt;/font&gt;&amp;nbsp;&lt;/p&gt;&lt;/div&gt;
&lt;div style="font-family: Times New Roman;"&gt;
&lt;table style="width: 95.34%; border-collapse: collapse; margin-left: 0.35in;" border="0" cellspacing="0" cellpadding="0" width="95%"&gt;
&lt;tr&gt;&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 72.74%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="72%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.64%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="text-align: center; margin: 0in 0in 0pt;" align="center"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: windowtext 1pt solid; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 23.58%; padding-right: 0in; border-top: medium none; border-right: medium none; padding-top: 0in;" valign="bottom" width="23%" colspan="5"&gt;
&lt;p style="text-align: center; margin: 0in 0in 0pt;" align="center"&gt;&lt;b&gt;&lt;font style="font-size: 8pt; font-weight: bold;" class="_mt" size="1"&gt;For&amp;nbsp;the&amp;nbsp;three&amp;nbsp;months&lt;br /&gt;ended&amp;nbsp;October&amp;nbsp;31,&lt;/font&gt;&lt;/b&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.04%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="1%"&gt;
&lt;p style="text-align: center; margin: 0in 0in 0pt;" align="center"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 72.74%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="72%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.64%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="text-align: center; margin: 0in 0in 0pt;" align="center"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: windowtext 1pt solid; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; border-top: medium none; border-right: medium none; padding-top: 0in;" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: center; margin: 0in 0in 0pt;" align="center"&gt;&lt;b&gt;&lt;font style="font-size: 8pt; font-weight: bold;" class="_mt" size="1"&gt;2010&lt;/font&gt;&lt;/b&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.62%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="text-align: center; margin: 0in 0in 0pt;" align="center"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: windowtext 1pt solid; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; border-top: medium none; border-right: medium none; padding-top: 0in;" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: center; margin: 0in 0in 0pt;" align="center"&gt;&lt;b&gt;&lt;font style="font-size: 8pt; font-weight: bold;" class="_mt" size="1"&gt;2009&lt;/font&gt;&lt;/b&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.04%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="1%"&gt;
&lt;p style="text-align: center; margin: 0in 0in 0pt;" align="center"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 72.74%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="72%"&gt;
&lt;p style="text-indent: -10pt; margin: 0in 0in 0pt 10pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.64%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: medium none; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; border-top: medium none; border-right: medium none; padding-top: 0in;" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.62%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: medium none; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; border-top: medium none; border-right: medium none; padding-top: 0in;" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.04%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 72.74%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="top" width="72%"&gt;
&lt;p style="text-indent: -10pt; margin: 0in 0in 0pt 10pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;Common unitholders' interest in net loss&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.64%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.3%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;$&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 9.18%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="9%"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;(27,763&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.62%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;)&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.3%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;$&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 9.18%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="9%"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;(32,338&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.04%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;)&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 72.74%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="72%"&gt;
&lt;p style="text-indent: -10pt; margin: 0in 0in 0pt 10pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.64%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.62%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.04%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 72.74%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="top" width="72%"&gt;
&lt;p style="text-indent: -10pt; margin: 0in 0in 0pt 10pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;Weighted average common units outstanding&lt;br /&gt;&lt;i&gt;(in thousands)&lt;/i&gt;&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.64%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;69,559.6&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.62%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;68,507.9&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.04%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 72.74%; padding-right: 0in; padding-top: 0in;" valign="top" width="72%"&gt;
&lt;p style="text-indent: -10pt; margin: 0in 0in 0pt 10pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.64%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.62%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.04%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 72.74%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="top" width="72%"&gt;
&lt;p style="text-indent: -10pt; margin: 0in 0in 0pt 10pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;Dilutive securities&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.64%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: windowtext 1pt solid; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; background: #cceeff; border-top: medium none; border-right: medium none; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;&amp;#8212;&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.62%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: windowtext 1pt solid; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; background: #cceeff; border-top: medium none; border-right: medium none; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;&amp;#8212;&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.04%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 72.74%; padding-right: 0in; padding-top: 0in;" valign="top" width="72%"&gt;
&lt;p style="text-indent: -10pt; margin: 0in 0in 0pt 10pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.64%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: medium none; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; border-top: medium none; border-right: medium none; padding-top: 0in;" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.62%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: medium none; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; border-top: medium none; border-right: medium none; padding-top: 0in;" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.04%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 72.74%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="top" width="72%"&gt;
&lt;p style="text-indent: -10pt; margin: 0in 0in 0pt 10pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;Weighted average common units outstanding plus dilutive securities&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.64%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: windowtext 3px double; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; background: #cceeff; border-top: medium none; border-right: medium none; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;69,559.6&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.62%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: windowtext 3px double; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; background: #cceeff; border-top: medium none; border-right: medium none; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;68,507.9&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.04%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 72.74%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="72%"&gt;
&lt;p style="text-indent: -10pt; margin: 0in 0in 0pt 10pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.64%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: medium none; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; border-top: medium none; border-right: medium none; padding-top: 0in;" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.62%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="border-bottom: medium none; border-left: medium none; padding-bottom: 0in; padding-left: 0in; width: 10.48%; padding-right: 0in; border-top: medium none; border-right: medium none; padding-top: 0in;" valign="bottom" width="10%" colspan="2"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.04%; padding-right: 0in; padding-top: 0in;" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 72.74%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="top" width="72%"&gt;
&lt;p style="text-indent: -10pt; margin: 0in 0in 0pt 10pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;Basic and diluted net loss per common unitholders' interest&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.64%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&amp;nbsp;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.3%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;$&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 9.18%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="9%"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;(0.40&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 2.62%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="2%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;)&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.3%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;$&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 9.18%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="9%"&gt;
&lt;p style="text-align: right; margin: 0in 0in 0pt;" align="right"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;(0.47&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;
&lt;td style="padding-bottom: 0in; padding-left: 0in; width: 1.04%; padding-right: 0in; background: #cceeff; padding-top: 0in;" bgcolor="#cceeff" valign="bottom" width="1%"&gt;
&lt;p style="margin: 0in 0in 0pt;"&gt;&lt;font style="font-size: 10pt;" class="_mt" size="2"&gt;)&lt;/font&gt;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt; &lt;/div&gt;</NonNumbericText><NonNumericTextHeader>J.&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp; Net loss per common unitholders' interest
 &amp;nbsp;
Below is a calculation of</NonNumericTextHeader><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios></Cell></Cells><OriginalInstanceReportColumns /><Unit>Other</Unit><ElementDataType>us-types:textBlockItemType</ElementDataType><SimpleDataType>string</SimpleDataType><ElementDefenition>This element may be used to capture the complete disclosure pertaining to an entity's earnings per share.</ElementDefenition><ElementReferences>Reference 1: http://www.xbrl.org/2003/role/presentationRef
 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 128
 -Paragraph 40

</ElementReferences><IsTotalLabel>false</IsTotalLabel><IsEPS>false</IsEPS><Label>Net loss per common unitholders' interest</Label></Row></Rows><Footnotes /><NumberOfCols>1</NumberOfCols><NumberOfRows>1</NumberOfRows><ReportName>Net loss per common unitholders' interest</ReportName><MonetaryRoundingLevel>UnKnown</MonetaryRoundingLevel><SharesRoundingLevel>UnKnown</SharesRoundingLevel><PerShareRoundingLevel>UnKnown</PerShareRoundingLevel><ExchangeRateRoundingLevel>UnKnown</ExchangeRateRoundingLevel><HasCustomUnits>false</HasCustomUnits><SharesShouldBeRounded>true</SharesShouldBeRounded></InstanceReport>
