Forrester's research shows that a key driver of loyalty for consumers is customer advocacy — the perception on the part of customers that a firm does what's best for them, not just what's best for the firm's own bottom line. Loyalty will become especially important to one segment in particular: the biggest US banks. Why? The federal government won't let them grow further by acquiring other banks. Marketing leaders at banks — and at other huge firms with narrowing customer acquisition opportunities like mobile operators — must relearn the lessons of organic growth. Forrester recently published a report on what big financial firms can do to earn greater customer loyalty.