Additional information 322 Any security Aegon issues in significant volume may be issued at higher financing costs if funding conditions are impaired, as they have  been from time to time in recent years. The requirement to issue securities can be driven by a variety of factors, for instance Aegon may  need liquidity for operating expenses, debt servicing and the maintenance of capital levels of insurance subsidiaries. Although Aegon  manages its liquidity position for extreme events, including greatly reduced liquidity in capital markets, if these conditions were to  persist for an extended period of time, Aegon may need to sell assets substantially below prices at which they are currently recorded to  meet its insurance obligations. In 2013, approximately 40% of Aegon’s general account investments were not highly liquid. Aegon’s earnings depend significantly upon the extent to which actual claims experience is consistent with the assumptions used in  setting the prices for Aegon’s products and establishing the technical liabilities for expected claims. If actual claims experience is less  favorable than the underlying assumptions used in establishing such liabilities, Aegon’s income would be reduced. Furthermore, if less  favorable claims experience became sustained, Aegon may be required to increase liabilities for other related products, which may  reduce Aegon’s income. In addition, certain acquisition costs related to the sale of new policies and the purchase of policies already in  force have been recorded as assets on the balance sheet and are being amortized into income over time. If the assumptions relating to  the future profitability of these policies (such as future claims, investment income and expenses) are not realized, the amortization of  these costs may be accelerated and may require write-offs due to an expectation of unrecoverability. This may have a materially  adverse effect on Aegon's results of operations and financial condition. Sources of underwriting risk include policy lapses, policy claims (such as mortality and morbidity) and expenses. In general, Aegon is at  risk if policy lapses increase, as sometimes Aegon is unable to fully recover up-front sales expenses despite the presence of  commission recoveries or surrender charges and fees. In addition, some policies have embedded options which at times are more  valuable to the client if they stay (lower lapses) or leave (higher lapses), which may result in losses to Aegon's businesses. Aegon sells  certain types of policies that are at risk if mortality or morbidity increases, such as term life insurance and accident insurance. Aegon  also sells certain other types of policies, such as annuity products, that are at risk if mortality decreases (longevity risk). For example,  certain current products as well as products sold in previous years based on standard longevity assumptions have become less  profitable or unprofitable as longevity assumptions increase, which may result in Aegon incurring losses. If the trend toward increased  longevity persists, Aegon’s annuity products may continue to experience adverse effects because the period of time over which benefit  payments are made becomes longer as life expectancies increase. Aegon is also at risk if expenses are higher than assumed. Reliance on various (financial) models to establish key results and assumptions is critical to Aegon’s operations. If these models prove  to be inaccurate, the same may apply to assumptions that are based thereon. Aegon’s earnings depends significantly on models and  assumptions used. Whereas the assumptions used to set the price for Aegon’s products, the inaccuracy of our financial models could  have a significant adverse effect on Aegon’s business. The valuation of many of Aegon’s financial instruments is based on methodologies, estimations and assumptions that are subject to  different interpretations and may result in changes to investment valuations that may have a materially adverse effect on Aegon’s  results of operations and financial condition. In addition, the determination of the amount of allowances and impairments taken on  Aegon’s investments is subjective and may materially impact Aegon’s results of operations or financial position. Valuation of Aegon’s investments, allowances and impairments is subjective, and discrepant valuations may adversely affect  Aegon’s results of operations and financial condition. Other risks Inaccuracies in (financial) models could have a significant adverse effect on Aegon’s business, results of operations and  financial condition. Modelling risk Differences between actual claims experience and underwriting and reserve assumptions may require liabilities to be  increased. Underwriting risk Annual Report 2013