171 Available-for-sale shares include shares in the Federal Home Loan Bank of EUR 94 million that are measured at par, which are reported  as part of Other. The bank has implicit financial support from the United States government. The redemption value of the shares is  fixed at par and they can only be redeemed by the bank. The table above presents the impact on a fair value measurement of a change in an unobservable input for financial instruments.  The impact of changes in inputs may not be independent, therefore the descriptions provided below indicate the impact of a change  in an input in isolation. e. To determine the fair value of the bifurcated embedded derivatives related to guarantees, a discount rate is used including credit  spread. An increase in the credit spread results in lower valuation, while a decrease results in a higher valuation of the embedded  derivatives. Aegon increased or decreased the credit spread by 20 basis points. d. The derivative included is a longevity index derivative. Most significant unobservable input is expected mortality. Changing  the expected mortality changes the cash flow expectations from this derivative. Increasing (decreasing) the mortality rates  decreases (increases) the value of the investment. Aegon adjusted longevity with 2% up or down for this input, compared to  the expected mortality in determining the value of this derivative. c. Tax credit investments are measured at fair value using an internal model. The most significant unobservable input for valuation  of these tax credits is the discount rate. Increasing or decreasing the discount rate would result in respectively a lower or higher  valuation. Aegon adjusted the discount rate by 50 basis points up or down for this input.  b. For corporate bonds the most significant unobservable input for the valuation of these securities is the credit spread. An increase  in credit spread results in a lower valuation, while a decrease in credit spread results in a higher valuation. Aegon adjusted  the discount rate by 50 basis points up or down for this input. a. The primary unobservable assumptions used in fair value measurement of asset backed securities is in general a liquidity premium  in the discount rate. Changing the liquidity premium changes the discount rate when using the discounted cash flow model.  Increasing or decreasing the liquidity premium respectively decreases or increases the value of the investment. Aegon adjusted  the discount rate with 100 basis points up or down for this input. December 31,  2013 Significant  unobservable  input Effect of reasonably  possible alternative  assumptions (+/-) Increase Decrease Financial assets carried at fair value Available­for­sale investments Debt securities ABS a 202 Discount rate 19 (20) Corporate bonds b 212 Credit spread 25 (19) Other investments at fair value Tax credit investments c 696 Discount rate 13 (13) Fair value through profit or loss Derivatives d 128 Mortality 11 (17) Financial liabilities carried at fair value Embedded derivatives in insurance contracts e 1,213 Credit spread 37 (36) Effect of changes in significant unobservable assumptions to reasonably possible alternatives