Bill Gates may have devoted much of his time to charitable causes in the last five years, but he is on the top of his league again as the richest man in the world with a personal net worth of $72.2 billion, according to Bloomberg.

This is the first time since 2007 that Mr Gates has been declared the richest with his expanded personal fortune, dislodging Mexican mobile phone magnate Carlos Slim

Mr Gates, who had spent three decades of his life at the forefront of computer innovation as chairman of Microsoft, reclaimed the crown from Mr Slim who took the top spot three years ago. Credit goes to Mr Gates's well of wise business investments and some help from the Mexican government, too.

Mr Slim's net wealth took a dive by 14 pervcent when the Mexican congress passed a bill geared towards breaking Mr Slim's monopoly of the country's telecommunications industry. His flagsship company, Merican Movil SAB, took the brunt that led to an almost $3 billion decline in Mr Slim's accounts.

Mr Gates, meanwhile, watched his wealth blossom by 15 percent as his portfolio of investments, including a significant stake in Microsoft, grew remarkably for a period.

But Mr Gates' biggest fortune lies in his interest with Cascade Investment LLC, a parent corporation that allows him to own shares of more than a dozen of publicly listed companies and other enterprises, including the luxurious Four Seasons Hotel.

Another American investor and philanthropist, Warren Buffet, according to the Bloomberg Billionaire's Index, is third place with a personal net worth of $59.7 billion.

Mr Buffet was $3.7 billion higher than Europe's richest person, Spanish Amancio Ortega Gaona, whose clothing firm Inditex owns the famous clothing chain Zara.

Since his retirement as chairman of Microsoft in 2008, Mr Gates has spent much of his time doing philanthropic works with his Bill and Melinda Gates Foundation, extending aid to a number of indigent beneficiaries around the world.

In 2012, a total of $750 million was donated by the multi-billionaire to the Global Fund on its tenth anniversary to fight AIDS, tuberculosis and malaria.

'These are tough economic times, but that is no excuse for cutting aid to the world's poorest,' Mr Gates said at the time, adding: 'The United States has a huge budget deficit so taxes are going to have to go up.

'I certainly agree that they should go up more on the rich than everyone else. That's just justice.'