II. Investment Portfolio Investment Securities . The following table sets forth the carrying value of the Company’s investment securities at  the dates indicated. None of the investment securities issued by an individual issuer held as of December 31, 2012 were in  excess of 10% of the Company’s stockholders’ equity, excluding U.S. federal agency obligations. The Company’s federal  agency obligations consist of obligations of U.S. government-sponsored enterprises, primarily the FHLB. The Company’s  mortgage-backed securities portfolio consists of securities predominantly underwritten to the standards and guaranteed by  the government-sponsored agencies of Federal Home Loan Mortgage Corporation (“FHLMC”), Federal National Mortgage  Association (“FNMA”) and Government National Mortgage Association (“GNMA”). The Company’s investments in  certificates of deposits consists of FDIC-insured certificates of deposits with other financial institutions.  The following table sets forth certain information regarding the carrying values, weighted average yields, and  maturities of the Company's investment securities portfolio, excluding common stocks, as of December 31, 2012. Yields on  tax-exempt obligations have been computed on a tax equivalent basis, using a 34% federal tax rate. Mortgage-backed  investment securities include scheduled principal payments and estimated prepayments based on observable market inputs. Actual prepayments will differ from contractual maturities because borrowers have the right to prepay obligations with or  without prepayment penalties.  2012 2011 2010 Investment securities: U.S. federal agency obligations  $ 8,848 $ 9,164 $ 22,187  Municipal obligations tax-exempt 77,286 69,629 65,287  Municipal obligations taxable 38,142 19,135 4,188  Mortgage-backed securities 81,848 94,472 60,804  Common stocks 902 819 828  Pooled trust preferred securities - 405 236  Certificates of deposits 6,274 4,590 14,159  Total available-for-sale investment securities, at fair value  $ 213,300 $ 198,214 $ 167,689  FHLB stock 3,360 4,850 6,364  FRB stock 1,765 1,761 1,759  Correspondent bank common stock 113 60 60  Total other securities, at cost  $ 5,238 $ 6,671 $ 8,183  As of December 31, (Dollars in thousands) Carrying Average Carrying Average Carrying Average Carrying Average Carrying Average value yield value yield value yield value yield value yield Investment securities: U.S. federal agency obligations 4,046 $ 0.77% 1,659 $ 1.38% 3,143 $ 1.41% - $ 0.00% 8,848 $ 1.11% Municipal obligations tax-exempt 4,127 5.24% 25,274 4.15% 39,485 4.98% 8,400 6.13% 77,286 4.85% Municipal obligations taxable 1,896 1.94% 20,065 1.65% 11,799 2.36% 4,382 3.98% 38,142 2.15% Mortgage-backed securities 4,287 2.55% 76,575 1.92% 404 3.26% 582 2.37% 81,848 1.96% Certificates of deposits 1,954 0.89% 4,320 0.83% - 0.00% - 0.00% 6,274 0.85% Total 16,310 $ 2.52% 127,893 $ 2.27% 54,831 $ 4.20% 13,364 $ 5.26% 212,398 $ 2.98% (Dollars in thousands) As of December 31, 2012 One year or less One to five years Five to ten years More than ten years Total 27 