Mumbai: Mukesh Ambani became India''s richest business head with the group''s market capitalisation rising to more than Rs4,00,000 crore, following a sharp surge in the share prices of his group companies.

Shares of his flagship company Reliance Industries and three other group firms - Reliance Petroleum, IPCL and Reliance Industrial Infrastructure -soared to an all-time high with gains ranging from 4-12 per cent.

Total investor wealth in the four companies surged to a total of Rs4,01,800 crore, led by RIL''s market value of Rs3,16,940 crore.

The sharp rally in the Mukesh Ambani group stocks widened the gap with his younger brother Anil Ambani group''s total market cap, which today stood at less than half the amount at Rs1,90,700 crore.