Superior's contractual obligations associated with its financial liabilities are as follows:
2018 and 2013 2014 2015 2016 2017 Thereafter Total----------------------------------------------------------------------------Borrowing 56.9 48.6 251.8 158.3 2.1 0.9 518.6Convertible unsecured subordinated debentures 24.7 67.5 - 72.1 167.8 144.3 476.4US$ foreign currency forward sales contracts (US$) 144.0 218.1 169.3 117.4 52.8 - 701.6US$ foreign currency forward purchases contracts (US$) (32.2) (27.2) - - - - (59.4)CDN$ natural gas purchases 15.3 3.6 0.8 0.4 0.2 - 20.3CDN$ butane purchases 1.0 1.0CDN$ propane purchases (CDN$) 2.0 0.1 0.1 - - - 2.2US$ propane purchases (US$) 1.0 - - - - - 1.0Fixed-price electricity purchase commitments - 17.7 17.7 17.7 17.7 - 70.8--------------------------------------------------------------------------------------------------------------------------------------------------------
Superior's contractual obligations are considered normal-course operating commitments and do not include the impact of mark-to-market fair values on financial and non-financial derivatives. Superior expects to fund these obligations through a combination of cash flow from operations, proceeds on revolving term bank credits and proceeds on the issuance of share capital. Superior's financial instruments' sensitivities as at March 31, 2013 are consistent with those disclosed in Superior's 2012 annual consolidated financial statements.
13. Income Taxes
Consistent with prior periods, Superior recognizes a provision for income taxes for its subsidiaries that are subject to current and deferred income taxes, including United States income tax and Chilean income tax.
Total income tax expense, comprised of current taxes and deferred taxes for the three months ended March 31, 2013 was $15.8 million, compared to $6.1 million in the comparative period. For the three months ended March 31, 2013 and March 31, 2012, deferred income tax expense from operations in Canada, the United States and Chile was $15.4 million and $5.9 million, respectively, which resulted in a corresponding total net deferred income tax asset of $283.8 million at March 31, 2013.
On April 2, 2013, Superior received a Notices of Reassessment for Superior's 2009 and 2010 taxation years reflecting the CRA's intent to challenge the tax consequences of Superior's corporate conversion transaction (Conversion) which occurred on December 31, 2008. The CRA's position is based on the acquisition of control rules, in addition to the general anti-avoidance rules in the Income Tax Act (Canada). The table below summarizes Superior's estimated tax liabilities and payment requirements associated with the received and anticipated Notices of Reassessment.
---------------------------------------------------------------------------- Taxes Payable 50% of the TaxesTaxation Year (1)(2) Payable (1)(2) Payment Dates----------------------------------------------------------------------------2009/2010 $13.0 $6.5 Paid in April 20132011 $10.0 (3) $5.0 Q2 20132012 $10.0 (3) $5.0 Q3 20132013 $20.0 (3) $10.0 Q3 2014----------------------------------------------------------------------------Total $53.0 $26.5--------------------------------------------------------------------------------------------------------------------------------------------------------(1) In millions of dollars(2) Includes estimated interest and penalties.(3) Estimated based on Superior's previously filed tax returns and the midpoint of Superior's 2013 outlook.



