As the Nasdaq share index set new records this week, Mr Gates saw his 20% share in Microsoft swell by $1bn, pushing his personal wealth into 12 figures.

With each of his one billion-plus shares in the Seattle-based software giant worth $93 (about �56), the 43-year-old's fortune could give most medium-sized national economies a run for their money.

He also has shareholdings in several other companies including $9bn invested in satellite ventures.

Windows has generated millions for Microsoft

The stage is now set for Mr Gates to become the world's first trillionaire.

The Daily Telegraph reports that having made about $4,566,000 for every hour of the past year, and with his wealth growing at the 61% compound annual rate it has enjoyed so far, he will hit the $1,000,000,000,000 mark in 2004.

The paper also states that his current wealth exceeds the economic output of all but the 18 wealthiest nations.

In fact, if his wealth continues to snowball, his fortune will overtake Britain's gross national product in 2005.

The latest news of Mr Gates's almost unfathomable personal wealth comes a few weeks after the public was granted an unprecedented insight into his financial affairs.

In an interview with Fortune Magazine, his fund manager Michael Larson said that except, of course, for Microsoft, this doyen of the computer industry generally gave Internet and technology shares a wide berth.

Cliveden, the stately home Gates bought last year

Mr Larson, who has managed the Gates finances since 1993, said the man who started off building computers in his garage was looking to cable TV companies and biotechnology firms for good returns in the future.

He has also channelled $9bn into a venture to surround the world with a network of 288 low-level satellites, which is due to launch around 2003.

However, these projects excepted, Mr Gates and Mr Larson have taken a rather unadventurous approach to investing the fortune.

"The point wasn't for Bill to become richer than the Sultan of Brunei," said Mr Larson.

Apart from Microsoft, most of Mr Gates's assets are held in relatively secure investments such as government and corporate bonds.