Citi, UBS, Merrill Lynch may face more writedowns

Three of the biggest mortgage and debt players in the country may face a fresh set of writedowns related to credit charges says Oppenheimer (and prescient bear) analyst Meredith Whitney.  These writedowns come on the heels of last week's rating cuts to AMBAC and MBIA insurance ratings . Bloomberg has the details: Citigroup Inc., Merrill Lynch & Co. and UBS AG may post further writedowns of $10 billion on their debt holdings after the two biggest bond insurers were stripped of their AAA rankings, according to Oppenheimer & Co. analyst Meredith Whitney. MBIA Inc. and Ambac Financial Group Inc., the world's largest bond insurers, had their AAA financial strength rankings reduced by Standard & Poor's June 5, taking with them the ratings on more than $1 trillion of