The stock market wipe-out caused by the global economic slowdown and the government's uncertain policy erased as many as 20 of India’s 60 billionaires, according to the study by ET Intelligence Group.

RPG Group's HV Goenka, Lanco Group's LM Rao, the Dhoot brothers of Videocon, GTL's Manoj Tirodkar and Tulsi Tanti of Suzlon are among the magnates who saw their holdings fall below the $1-billion mark, said The Economic Times.

No-one was immune to the difficult economic environment. The 40 remaining billionaires lost on average 38 per cent of their net worth.

At the top of the pile is still Mukesh Ambani, whose $34.7 billion of assets nearly halved in just 12 months to $19.1 billion. Sunil Bharti Mittal jumped up from third to second. He lost $4 billion off his $20.7 billion net worth, and is now worth $16.7 billion. Down to third place is Azim Premjl, who lost nearly a third from his $21.3 billion of assets, and is now woth $14.6 billion.

ET calculated the wealth or net worth of promoters by multiplying the market cap of listed entities with promoter holding exclusive of cross-holdings.

The effects of the global slowdown and the ongoing European debt crisis is being felt all over Asia, despite the strong growth predictions for the region. Earlier this week Forbes published its Hong Kong Rich List, to reveal that the city-state’s wealthiest billionaires had lost 7 per cent of their net worth, reported here.