bond insurer AMBAC lose AAA

-- Ambac Financial Group Inc., the firstbond insurer to lose its AAA credit rating because of subprimemortgages, is considering ``strategic alternatives'' afterposting its biggest-ever loss. The shares jumped 29 percent onoptimism the company may be sold. --The second-largest bond insurer posted a fourth-quarter netloss of $3.26 billion, or $31.85 a share, after writing down thevalue of credit-derivatives tied to loans made to homeowners withpoor credit by $5.21 billion, according to a statement by thecompany today.