1. Mr Warren Buffett has seen the value of equity in his company, Berkshire Hathaway, fall by about US$13.6 billion, or 22 per cent, so far this year, to leave his holdings valued at US$48.1 billion.

2. Oracle founder and CEO Larry Ellison has seen his equity stake fall by US$6.2 billion, or about 24 per cent, to US$20.1 billion.

3. Microsoft's Steve Ballmer, whose company equity fell by US$5.1 billion to US$9.4 billion.

4. Amazon.com's Jeff Bezos, whose equity fell by US$3.6 billion to US$5.7 billion

5. News Corp's Rupert Murdoch, with a US$4 billion contraction to US$3 billion.