100 NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS OF AEGON N.V.  NOTE 2.17 - 2.19 B. IMPAIRMENT OF DEBT INSTRUMENTS C. IMPAIRMENT OF EQUITY INSTRUMENTS continuing use and ultimate disposal of the asset and reflects  its known inherent risks and uncertainties.  Impairment losses are charged to shareholders’ equity to the  extent that they offset a previously recorded revaluation  reserve relating to the same item. Any further losses are  recognized directly in the income statement.  With the exception of goodwill, impairment losses are reversed  when there is evidence that there has been a change in the  estimates used to determine the asset’s recoverable amount  since the recognition of the last impairment loss. The reversal  is recognized in the income statement to the extent that it  reverses impairment losses previously recognized in the income  statement. The carrying amount after reversal cannot exceed  the amount that would have been recognized had no  impairment taken place.  Non-financial assets that only generate cash flows in combination  with other assets and liabilities are tested for impairment at  the level of the cash-generating unit. The goodwill acquired in a  business combination, for the purpose of impairment testing, is  allocated to cash-generating units, or groups of cash-generating  units, that are expected to benefit from the synergies of the  combination. The allocation is based on the level at which  goodwill is monitored internally and cannot be larger than an  operating segment. When impairing a cash-generating unit, any  goodwill allocated to the unit is first written-off and recognized  in the income statement. The remaining impairment loss is  allocated on a pro rata basis among the other assets, on  condition that the resulting carrying amounts do not fall below  the individual assets’ recoverable amounts.  original effective interest rate of the asset. For variable interest  debt instruments, the current effective interest rate under the  contract is applied.  For debt instruments classified as available-for-sale, the asset is  impaired to its fair value. Any unrealized gain or loss previously  recognized in other comprehensive income is taken to the  income statement in the impairment loss. After impairment  the interest accretion on debt instruments that are classified  as available-for-sale is based on the rate of return that would  be required by the market for similar rated instruments at the  date of impairment. Impairment losses recognized for debt instruments can be  reversed if in subsequent periods the amount of the impairment  loss decreases and that decrease can be objectively related to  a credit event occurring after the impairment was recognized.  For debt instruments carried at amortized cost, the carrying  amount after reversal cannot exceed its amortized cost at the  reversal date. For equity instruments, a significant or prolonged decline in  fair value below initial cost is considered objective evidence of  impairment and always results in a loss being recognized in the  income statement. Significant or prolonged decline is defined as  an unrealized loss position for generally more than 6 months or  a fair value of less than 80% of the cost price of the  investment. Equity investments are impaired to the asset’s  fair value and any unrealized gain or loss previously recognized  in shareholders’ equity is taken to the income statement as  an impairment loss. The amount exceeding the balance of  previously recognized unrealized gains or losses is recognized  in the income statement.  Impairment losses on equity instruments cannot be reversed. Debt instruments are impaired if there is objective evidence  that a loss event has occurred after the initial recognition of  the asset that has a negative impact on the estimated future  cash flows. A specific security is considered to be impaired  when it is determined that it is probable that not all amounts  due (both principal and interest) will be collected as scheduled.  Individually significant loans and other receivables are first  assessed separately. All non-impaired assets measured at  amortized cost are then grouped by credit risk characteristics  and collectively tested for impairment.  For debt instruments carried at amortized cost, the carrying  amount of impaired financial assets is reduced through an  allowance account. The impairment loss is calculated as the  difference between the carrying and recoverable amount of  the investment. The recoverable amount is determined by  discounting the estimated probable future cash flows at the  Reinsurance assets are impaired if there is objective evidence,  as a result of an event that occurred after initial recognition  of the reinsurance asset, that not all amounts due under the  terms of the contract will be received and the impact of the  event on the amount to be received from the reinsurer can  be reliably measured. Impairment losses are recognized in  the income statement.  D. IMPAIRMENT OF REINSURANCE ASSETS NOTE 2.17 EQUITY Financial instruments that are issued by the Group are  classified as equity if they represent a residual interest in the  assets of the Group after deducting all of its liabilities and the  Group has an unconditional right to avoid delivering cash or 