Banks may be lobbying hard to bring in deposits these days, but at least one source of bank revenue is up sharply. Revenue from banks' insurance fee income jumped 9.5 percent to $23.7-billion in the first half of the year. Leading the way were three institutions that are very active — or soon to be active — in the Florida market: Citigroup, Wells Fargo & Co. and BB&T Corp. The analysis by Michael White Associates and the American Bankers Insurance Association indicates banks are increasingly relying on niche insurance products. "Those institutions that engage in it are glad to have the additional income for diversification of their revenue sources and for their bottom lines," said Valerie Barton, executive director of the bankers insurance association.