Bloomberg Markets with Carol Massar and Cory Johnson.\u0010\u0010GUEST:\u0010David Wilson\u0010Stocks Editor\u0010Bloomberg News\u0010Discussing his "Stock of the Day" Ambac Financial Group (AMBC). Ambac Financial Group Inc.'s shares are headed for their biggest one-day gain since the bond insurer emerged from bankruptcy in 2013. The company reached a deal yesterday to settle litigation over subprime mortgage-linked contracts that were signed before the housing market collapsed a decade ago. Ambac estimated that the agreement will add about $361 million, or $8.02 a share, to its book value after completion.