After four months of withdrawal, foreign capital has begun returning to Indian equities, drawn by a market that has shown resilience in the face of global uncertainty. Yet the banking sector — the largest pillar of India's financial index — remains curiously untouched, not because its foundations are cracked, but because the economics of lending in a shifting rate environment have compressed the very margins that make banks worth owning. It is a reminder that in markets, as in life, the appearance of health and the experience of it are not always the same thing.