cash payments by Aegon requiring the sale of invested assets at a time when the prices of those assets are adversely affected by  the increase in market interest rates; this may result in realized investment losses. These cash payments to policyholders result in  a decrease in total invested assets and a decrease in net income. Among other things, early withdrawals may also require accelerated  amortization of DPAC, which in turn reduces net income. During periods of sustained low interest rates, Aegon may not be able to preserve margins as a result of minimum interest rate  guarantees and minimum guaranteed crediting rates provided on policies. Also, investment earnings may be lower because the interest  earnings on new fixed-income investments are likely to have declined with the market interest rates. Mortgages and redeemable  bonds in the investment portfolio are more likely to be repaid as borrowers seek to borrow at lower interest rates and Aegon may be  required to reinvest the proceeds in securities bearing lower interest rates. Accordingly, net income declines as a result of a decrease in  the spread between returns on the investment portfolio and the interest rates either credited to policyholders or assumed in reserves. Aegon manages interest rate risk closely taking into account all of the complexity regarding policyholder behavior and management  action. Aegon employs sophisticated interest rate measurement techniques and actively uses derivatives and other risk mitigation tools  to closely manage its interest rate risk exposure. Aegon operates an Interest Rate Risk policy that limits the amount of interest rate risk  to which the Group is exposed. All derivative use is governed by Aegon’s Derivative Use Policy. 2013 2012 2011 2010 2009 3-month US LIBOR 0.25% 0.31% 0.58% 0.30% 0.25% 3-month EURIBOR 0.29% 0.19% 1.36% 1.01% 0.70% 10-year US Treasury 3.03% 1.76% 1.88% 3.29% 3.83% 10-year Dutch government 2.23% 1.50% 2.19% 3.15% 3.56% The sensitivity analysis in the table below shows an estimate of the effect of a parallel shift in the yield curves on net income and  shareholders’ equity. In general, increases in interest rates have a negative effect on shareholders’ equity and a positive impact on net  income in the current year because it results in unrealized losses on investments that are carried at fair value. The rising interest rates  would also cause the fair value of the available-for-sale bond portfolio to decline and the level of unrealized gains could become too  low to support recoverability of the full deferred tax asset triggering an allowance charge to income. The offsetting economic gain  on the insurance and investment contracts is however not fully reflected in the sensitivities because many of these liabilities are not  measured at fair value. Over time, the medium-term reduction in net income due to rising interest rates would be offset by higher net  income in later years, all else being equal. Therefore, higher interest rates are not considered a long-term risk to the Group.  As premiums and deposits are received, these funds are invested to pay for future policyholder obligations. For general account  products, Aegon typically bears the risk for investment performance equaling the return of principal and interest. Aegon is exposed  to credit risk on its general account fixed-income portfolio (debt securities, mortgages and private placements), OTC derivatives and  reinsurance contracts. Some issuers have defaulted on their financial obligations for various reasons, including bankruptcy, lack of  liquidity, downturns in the economy, downturns in real estate values, operational failure and fraud. During the financial crisis, Aegon  incurred significant investment impairments on Aegon’s investment assets due to defaults and overall declines in the capital markets.  Further excessive defaults or other reductions in the value of these securities and loans could have a materially adverse effect on  Aegon’s business, results of operations and financial condition. Credit risk Parallel movement of yield curve Estimated approximate  effects on net income Estimated approximate  effects on shareholders'  equity 2013 Shift up 100 basis points 101 (3,445) Shift down 100 basis points (62) 3,436 2012 Shift up 100 basis points 66 (3,960) Shift down 100 basis points (52) 3,374 The following table shows interest rates at the end of each of the last five years.  177