Kotak Mahindra Bank

Founded in 1985, this ­Mumbai bank almost doubled its customer base—from 8 million to 14.5 million—between March 2017 and this summer. The growth spurt was ignited by Kotak Mahindra’s 2017 launch of 811, an effort at inclusive banking, that offers all Indians a digital bank account in less than five minutes. It’s cheap, too, with zero charges for digital transactions. The relatively small bank ($3.9 billion in 2017 net revenue) is now building out its branch network to physically be where its new customers are. Analysts project it’s on track for 25% annual growth.