Have you been paying attention to shares of Ambac Financial Group (AMBC) ? Shares have been on the move with the stock up 22.5% over the past month. The stock hit a new 52-week high of $18.45 in the previous session. Ambac Financial Group has gained 11.2% since the start of the year compared to the 2.7% move for the Zacks Finance sector and the 14.2% return for the Zacks Insurance - Property and Casualty industry.What's Driving the Outperformance?The stock has an impressive record of positive earnings surpr ...