After hosting investor meetings with management, JPMorgan analyst Steven Alexopoulos says he finds shares of Signature Bank "bargain." The company's net interest margin and credit quality likely to hold "relatively stable," which provides a favorable backdrop for its newest three verticals -- funds banking, venture banking and mortgage servicing banking -- to start ramping growth, Alexopoulos tells investors in a research note. He sees the potential growth from these new verticals as being "significantly undervalued" with Signature Bank shares trading in line with peers. The analyst keeps an Overweight rating on the shares with a $138 price target.