On September 30, 2016, we entered into a credit agreement providing for a $100 million term loan that matures on September 30, 2019 and a $150 million unsecured revolving line of credit that matures on September 30, 2021. The $100 million of loan proceeds were contributed to the capital and surplus of American Equity Life on October 3, 2016.
Our 2015 notes matured and were extinguished on September 15, 2015, and the 2015 notes hedges expired on that same date. The fair value of the 2015 notes hedges changed based upon changes in the price of our common stock, interest rates, stock price volatility, dividend yield and the time to expiration of the 2015 notes hedges. Similarly, the fair value of the conversion option obligation to the holders of the 2015 notes changed based upon these same factors and the conversion option obligation was accounted for as an embedded derivative liability with changes in fair value reported in the Change in fair value of embedded derivatives. The amount of the change in fair value of the 2015 notes hedges was typically equal to the amount of the change in the related embedded derivative liability and there typically was an offsetting expense in the change in fair value of embedded derivatives. Due to the partial unwind agreements we entered into in 2014, the decrease in the change in the fair value of the 2015 notes embedded derivative conversion liability exceeded the decrease in the fair value of the 2015 notes hedges by $10.1 million for the year ended December 31, 2014. See Note 5 to our audited consolidated financial statements for a discussion of the unwind agreements, the 2015 notes hedges and the 2015 notes embedded derivative conversion liability.
Net OTTI losses recognized in operations increased to $22.7 million in 2016 and increased to $19.5 million in 2015 from $2.6 million in 2014. The impairments recognized in 2016 were primarily on three corporate securities with exposure to the telecommunications, materials and energy sectors and two asset-backed securities with exposure to the energy sector. The impairments recognized in 2015 were primarily on two corporate securities with exposure to the metals and mining sector and one asset-backed security with exposure to the energy sector. The impairments recognized in 2014 were on residential mortgage backed securities and were principally due to changes of assumptions regarding loss severity of a number of securities we hold which affected our ongoing analysis of expected cash flow projections. See Financial Condition-Investments and Note 3 to our audited consolidated financial statements for additional discussion of write downs of securities for other than temporary impairments.
See Net income and Operating income, a non-GAAP financial measure, above for discussion of the impact of unlocking on amortization of deferred policy acquisition costs for the years ended December 31, 2016, 2015 and 2014. See Critical Accounting Policies-Deferred Policy Acquisition Costs and Deferred Sales Inducements.
The following table presents the fair value of fixed maturity and equity securities, available for sale, by pricing source and hierarchy level as of December 31, 2016 and 2015, respectively:
We validate external valuations at least quarterly through a combination of procedures that include the evaluation of methodologies used by the pricing services, analytical reviews and performance analysis of the prices against trends, and maintenance of a securities watch list. Additionally, as needed we utilize discounted cash flow models or perform independent valuations on a case-by-case basis using inputs and assumptions similar to those used by the pricing services. Although we do identify differences from time to time as a result of these validation procedures, we did not make any significant adjustments as of December 31, 2016 and 2015.