The change in VIE investment related gains and losses decreased by $86 million to $(53) million in 2016 from $33 million in 2015, primarily driven by a decline in market value of public equity positions in one of our funds, as the share prices of these public equity positions decreased in 2016 compared to 2015. The decrease was partially offset by a $60 million favorable increase in the fair value of certain underlying investments in three of our consolidated VIEs, reflecting the removal of liquidity discounts related to marketability assumptions used in the determination of the fair value of certain of the investments, resulting in $82 million of gains in 2016 compared to $22 million of gains in 2015.
Future policy benefits decreased by $179 million to $517 million in 2015 from $696 million in 2014, primarily attributable to the $236 million decrease in the change in AmerUs Closed Block fair value liability, which was related to unrealized losses on the underlying investments attributable to the decrease in U.S. treasury rates. Additionally, gains recognized from favorable mortality experience contributed to the decrease in future policy benefits which were partially offset by an increase in benefits from the DLD acquisition. The rider reserves change was consistent with 2014 as the increase from equity market performance and higher than expected persistency was offset by favorable unlocking of lapse rate assumptions and the decrease related to changes in FIA embedded derivatives and investment related gains and losses.
Operating income, net of tax increased by $5 million, or 1%, to $769 million in 2015 from $764 million in 2014. Operating ROE excluding AOCI declined to 22.7% in 2015 from 32.2% in 2014, reflecting the increase in equity allocated to Retirement Services as we increased our capital within Retirement Services which management considered necessary to support the segment's growth and our ratings aspirations. The increase in operating income, net of tax was primarily driven by the increase in net investment income as we continued to reinvest the Aviva USA acquired investments during 2015 as well as an increase in rider charges over the change in rider reserves. The increases in operating income, net of tax were offset by an increase in amortization of DAC, DSI, and VOBA.
The following summarizes the underlying investment composition of the funds withheld at interest:
CMBS with weighted average lives less than three years rated AAA- or above;
The ability of AHL’s insurance subsidiaries to pay dividends is limited by applicable laws and regulations of the jurisdictions where the subsidiaries are domiciled, as well as agreements entered into with regulators. These laws and regulations require, among other things, the insurance subsidiaries to maintain minimum solvency requirements and limit the amount of dividends these subsidiaries can pay.
We are a member of the FHLBDM and the FHLBI. Membership in a FHLB requires the member to purchase FHLB common stock based on a percentage of the dollar amount of advances outstanding, subject to the investment being greater than or equal to a minimum level. We owned a total of $40 million and $56 million of FHLB common stock as of December 31, 2016 and 2015, respectively.
Through our membership in the FHLBDM and FHLBI, we are eligible to borrow under variable rate short-term federal funds arrangements to provide additional liquidity. The borrowings must be secured by eligible collateral such as mortgage loans, eligible CMBS or RMBS, government or agency securities and guaranteed loans. There were no outstanding borrowings under these arrangements as of December 31, 2016 or 2015.
We issue and reinsure products, primarily FIA products, or purchase investments that contain embedded derivatives. If we determine the embedded derivative has economic characteristics not clearly and closely related to the economic characteristics of the host contract, and a separate instrument with the same terms would qualify as a derivative instrument, the embedded derivative is bifurcated from the host contract and accounted for separately. Embedded derivatives are carried on the consolidated balance sheets at fair value in the same line item as the host contract. Changes in the fair value of embedded derivatives associated with FIAs are reflected in interest sensitive contract benefits on the consolidated statements of income. Embedded derivatives that are not clearly and closely related to the host contract within a financial asset are required to be bifurcated and recorded at fair value unless the fair value option is elected on the host contract. Under the fair value option, bifurcation of the embedded derivative is not necessary as all related gains (losses) on the host contract and derivative will be reflected within investment related gains (losses) on the consolidated statements of income.
suitable to hedge with options that align with index terms of our FIA products because policyholder accounts are credited with index performance at the end of each index term. However, because the value of an embedded derivative in an FIA contract is longer-dated, there is a duration mismatch which may lead to mismatches for accounting purposes.
The cost of other invested assets is adjusted for impairments in value deemed to be other-than-temporary in the period in which the determination is made. These impairments are included within other-than-temporary impairment losses, and the cost basis of the investment securities is reduced accordingly. We do not change the revised cost basis for subsequent recoveries in value.
Accounting for reinsurance requires the use of assumptions upon agreement inception, particularly related to the future performance of the underlying business and the potential impact of counterparty credit risks. We attempt to minimize our counterparty credit risk through the structuring of the terms of our reinsurance agreements, including the use of trusts, and we monitor credit ratings of counterparties for signs of declining credit quality. When a ceding company does not report information on a timely basis, we record accruals based on the best available information at the time, which includes the reinsurance agreement terms and historical experience. We periodically compare actual and anticipated experience to the assumptions used to establish reinsurance assets and liabilities. Refer to Note 7 - Reinsurance for more information.
As of December 31, 2016 and 2015, all of the non-separate account unit-linked policies were paying dividends, and the related liability is recorded in dividends payable to policyholders on the consolidated balance sheets. There were no material deposits related to non-separate account unit-linked policies paying dividends for the years ended December 31, 2016 and 2015. Non-separate account unit-linked policies represented an insignificant percentage of our interest sensitive contracts in force as of December 31, 2016 and 2015.
This update is intended to increase transparency and comparability for lease transactions. A lessee is required to recognize an asset and a liability for all lease arrangements longer than 12 months. Lessor accounting is largely unchanged. We will be required to adopt this standard on a modified retrospective basis effective January 1, 2019. Early adoption is permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements.
Proceeds from sales of AFS securities were $4,662 million, $6,899 million and $6,391 million for the years ended December 31, 2016, 2015 and 2014, respectively.
Real Estate-Depreciation expense on invested real estate was $9 million and $2 million during the years ended December 31, 2016 and 2015, respectively. Accumulated depreciation was $11 million and $2 million as of December 31, 2016 and 2015, respectively.
Total return swaps - We purchase total rate of return swaps to gain exposure and benefit from a reference asset without ownership. Total rate of return swaps are contracts in which one party makes payments based on a set rate, either fixed or variable, while the other party makes payments based on the return of the underlying asset, which includes both the income it generates and any capital gains.
As of December 31, 2016 or 2015, no additional collateral would be required if a default or termination event were to occur.
Fixed Maturity Securities - We invest in securitization entities as a debt holder or an investor in the residual interest of the securitization vehicle, which are included in fixed maturity securities on the consolidated balance sheets. These entities are deemed VIEs due to insufficient equity within the structure and lack of control by the equity investors over the activities that significantly impact the economics of the entity. In general, we are a debt investor within these entities and, as such, hold a variable interest; however, due to the debt holders' lack of ability to control the decisions within the trust that significantly impact the entity, and the fact the debt holders are protected from losses due to the subordination by the equity tranche, the debt holders are not deemed the primary beneficiary. Securitization vehicles in which we hold the residual tranche are not consolidated because we do not unilaterally have substantive rights to remove the general partner, or when assessing related party interests, we are not under common control, as defined by GAAP, with the related party, nor are substantially all of the activities conducted on our behalf; therefore, we are not deemed the primary beneficiary. Debt investments and investments in the residual tranche of securitization entities are considered debt instruments and are held at fair value on the balance sheet and classified as AFS or trading.
The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). If the inputs used to measure fair value fall within different levels of the hierarchy, the category level is based on the lowest priority level input that is significant to the instrument's fair value measurement.
We estimate the fair value for financial instruments not carried at fair value using the same methods and assumptions as those we do carry at fair value. The financial instruments presented above are reported at carrying value on the consolidated balance sheets; however, in the case of policy loans, funds withheld at interest and liability, other investments and related party short-term investments, the carrying amount approximates fair value.
Credit Facility-In 2016, AHL, ALRe and Athene USA entered into a five-year revolving credit agreement (Credit Facility) with Citibank, N.A., as administrative agent. The borrowing capacity under the Credit Facility is $1 billion. In connection with the Credit Facility, AHL and Athene USA guaranteed all of the obligations of AHL, ALRe and Athene USA under this facility, and ALRe guaranteed certain of the obligations of AHL and Athene USA under this facility. The Credit Facility contains various standard covenants with which we must comply, including the following:
As of December 31, 2016, we had no amounts outstanding under the Credit Facility and were in compliance with all covenants under this facility.
Conversion to Class A shares - Vested Class M shares became eligible for conversion to Class A shares at IPO or as a result of the 2016 Modification, subject to the conversion rate for each Class M share. A holder of vested Class M shares may elect to exchange vested shares for an equivalent number of Class A shares upon payment, in cash or shares, of the conversion price less the amount of any dividends paid by the Company on Class A shares subsequent to the granting of Class M shares. Following a conversion to Class A shares, shares can be sold subject to contractual transfer or legal restrictions, such as lockups, blackout periods or affiliate sale volume caps.
We use the two-class method for allocating net income available to AHL shareholders to each class of our common stock. Our Class M shares do not become eligible to participate in dividends until a return of investment (ROI) condition has been met for each class. Once eligible, each class of our common stock has equal dividend rights. Prior to the fourth quarter of 2016, the ROI condition had not been met for any of our Class M shares and as a result, no earnings were attributable to those classes. In conjunction with our IPO, the ROI condition for Class M-1 was met, while Class M-2, Class M-3 and Class M-4 shares remain ineligible for dividends as of December 31, 2016. Therefore, the basic EPS calculations above reflect only those classes of stock eligible to participate in earnings during each respective period. For the years ended December 31, 2015 and 2014, Class A and B had the same basic and dilutive EPS, and as such are presented together for those years.
call options associated with the current index interest crediting term are valued at zero. AAIA has elected to apply this option to its over-the-counter call options and reserve liabilities. As a result, AAIA's statutory surplus decreased by $17 million and increased by $14 million as of December 31, 2016 and 2015, respectively.
We have a management investment committee, which includes members of our senior management and reports to the risk committee of our board of directors. The committee focuses on strategic decisions involving our investment portfolio, such as approving investment limits, new asset classes and our allocation strategy, reviewing large asset transactions, as well as monitoring our credit risk, and the management of our assets and liabilities.
In 2000 and 2001, two insurance companies which were subsequently merged into AAIA purchased from American General Life Insurance Company (American General) broad based variable corporate-owned life insurance (COLI) policies that, as of December 31, 2016, had an asset value of $327 million, and is included in other assets on the consolidated balance sheets. In January 2012, the COLI policy administrator delivered to AAIA a supplement to the existing COLI policies and advised that American General and ZC Resource Investment Trust (ZC Trust) had unilaterally implemented changes set forth in the supplement that if effective, would: (1) potentially negatively impact the crediting rate for the policies and (2) change the exit and surrender protocols set forth in the policies. In March 2013, AAIA filed suit against American General, ZC Trust, and ZC Resource LLC in Chancery Court in Delaware, seeking, among other relief, a declaration that the changes set forth in the supplement were ineffectual and in breach of the parties’ agreement. The parties filed cross motions for judgment as a matter of law, and the court granted defendants’ motion and dismissed without prejudice on ripeness grounds. The issue that negatively impacts the crediting rate for one of the COLI policies has been triggered and we will pursue further adjudication. If the supplement is ultimately deemed to be effective, the purported changes to the policies could impair AAIA’s ability to access the value of guarantees associated with the policies. The value of the guarantees included within the asset value reflected above are $159 million as of December 31, 2016.