December 31, 2000 Gross Gross Amortized Fair Unrealized Unrealized Cost Value Gains Losses Fixed maturities held to maturity at amortized cost: Bonds and notes: United States government $ 8,765 $ 9,393 $ 628 $ —  State and munici- pal obligations 460,826 481,399 21,070 497  $ 469,591 $ 490,792 $21,698 $ 497  Fixed maturities available for sale: Bonds and notes: United States government $ 33,126 $ 33,527 $ 756  $ 355 State and munici- pal obligations 822,501 848,048 28,541 2,994  Corporate 152,052 157,115 8,807 3,744  Asset-backed  securities 59,200 60,031 1,146 315  Redeemable  preferred stock 20,312 22,119 2,437 630  $1,087,191 $1,120,840 $41,687 $8,038  Equity securities available for sale $ 58,877 $ 64,202 $12,684 $7,359 The contractual maturities of fixed maturity investments are as follows (in thousands): December 31, 2001  Amortized Cost Fair Value  Fixed maturities held to maturity:  2002 $ 23,723 $ 23,754  2003–2006 125,760 132,106  2007–2011 186,266 196,525  2012 and thereafter 106,449 109,577  $ 442,198 $ 461,962 Fixed maturities available for sale:  2002  $ 19,104  $ 18,524 2003–2006 301,250 309,324  2007–2011 339,413 342,513  2012 and thereafter 1,718,111 1,721,779  Asset-backed securities 149,670 149,700  Redeemable preferred stock 25,382 25,360 $2,552,930 $2,567,200 Net investment income consisted of (in thousands): Year Ended December 31  2001 2000 1999  Investment income: Fixed maturities $139,508 $79,891 $66,090  Equity securities 1,772 1,461 636  Short-term investments 7,597 3,941 1,789  Other 3,749 1,272 667  152,626 86,565 69,182  Investment expenses (5,139) (3,619) (1,923) $147,487 $82,946 $67,259 Net gain on sales of investments consisted of (in thousands): For the year ended December 31, 2001, the Company did not sell any fixed maturity investments held to maturity.  For the year ended December 31, 2000, the Company sold  fixed maturity investments held to maturity with an amortized  cost of $1,949,000 resulting in losses of $27,000, and for the year ended December 31, 1999, the Company sold a fixed maturity investment held to maturity with an amortized cost of $10,000 that resulted in no gain or loss. All investments were sold in response to a significant deterioration in the issuer’s creditworthiness. Net change in unrealized appreciation (depreciation)  on investments consisted of (in thousands): Securities on deposit with various state insurance commissioners amounted to $17,512,000 at December 31, 2001 and $13,086,000 at December 31, 2000. The Company also had $596,965,000 on deposit at December 31, 2001 for the benefit of reinsurers. > 27 Year Ended December 31 2001 2000 1999  Gains on sales and redemptions of fixed  maturity investments available for sale $ 22,336 $ 12,732 $ 3,213  Losses on sales and  redemptions of fixed  maturity investments available for sale (13,782) (9,115) (1,752)  Gains on sales and  redemptions of fixed  maturity investments held to maturity 59 4 27  Losses on sales and  redemptions of fixed  maturity investments held to maturity (84) (35) (10)  Gains on sales of equity securities available for sale 39 2,206 273  Losses on sales of equity securities available for sale (943) (1,767) (183)  Losses on sales of other invested assets (1,058) — — Gains on sales of trading securities 521 — — Losses on sales of trading securities (669) — — Gains on sales of short-term investments 5 184 —  Losses on sales of short-term investments — (30) —  $ 6,824 $ 4,179 $ 1,568 Year Ended December 31 2001 2000 1999  Fixed maturities held to maturity $ (1,437) $ 14,493 $(28,142) Fixed maturities available for sale $(19,379) $ 68,718 $(59,636)  Deferred tax benefit (provision) 6,725 (24,051) 20,873  $(12,654) $ 44,667 $(38,763) Equity securities available for sale $ (1,983) $ (5,334) $ 8,343  Deferred tax benefit (provision) 695 1,867 (2,920)  $ (1,288)  $ (3,467)  $ 5,423  Other $ (365) — —