New Delhi, June 2 -- For nearly three decades, investor Devina Mehra has built her portfolio around a simple principle: never let a single market determine your financial future.

The approach paid off over the past year. While her Indian equity portfolio delivered 0% returns, the global portion returned 39% in rupee terms.

"The 1997 Asian financial crisis was a wake up call for me that a single market risk is not worth it. No matter how well a country is growing in a year, a single crisis can wipe out most of your wealth," said the founder and managing director of First Global, who began investing overseas in 1999.

"India is not even 3% of the world market cap, so there is no reason why investors' entire investment should be in India,"...