Ambac (ABK) and MBIA (MBI) sank along with the broader market Friday, after the investors in the bond insurers got hit with a bevy of bad news. First, billionaire vulture investor Wilbur Ross said he would sink as much as $1 billion into rival Assured Guaranty (AGO), bolstering the company’s capital position and giving it a chance to benefit from the uncertainty surrounding MBIA and Ambac. Then CNBC reported that talks regarding a $2.5 billion capital-raising effort for Ambac have hit a snag, with ratings agencies apparently demanding a bigger infusion, though the channel stressed that discussions continue. Last but not least, MBIA - which took some $4 billion in mark-to-market losses in its fourth quarter to account for declines in the market value of its derivatives portfolios - said on page 28 of its annual report that it expects further mark-to-market writedowns in January. Approaching midday, Assured Guaranty was up 12% and MBIA and Ambac were each down 5%. But recent history shows that if Ambac is able to work out a deal with its bankers Friday afternoon, shares of it and MBIA - as well as the big market indexes - could reverse course in a big way.