Microsoft founder Bill Gates looks to have lost his title as the world's richest man, toppled from top spot by the Mexican telecoms tycoon Carlos Slim.

Three months ago the cigar-chomping Mr Slim quietly slipped past legendary US investor Warren Buffett to take second place in the global wealth league.

Now, thanks to a surge in the shares of his America Movil group, Mr Slim has claimed pole position, according to the Mexican online financial publication, Sentido Común.

It was Sentido Común's founder, Eduardo Garcia, who highlighted Mr Slim's rapidly rising wealth in April, although by his calculations the Mexican had not only beaten Mr Buffett in the wealth stakes by then but also edged past Mr Gates.

Now, however, Mr Garcia says there is no doubt that the little-known Mexican has finally captured the coveted top slot, following a surge in America Movil's shares over the second quarter. This is estimated to have boosted his fortune to an estimated $67.8bn (£33.6bn) - equivalent to 8% of Mexico's gross domestic product - compared with $59.2bn for the Microsoft mogul, putting him in the lead by a decisive $8.6bn.

"When I put Slim ahead three months ago Forbes bumped him up to second place (in world rankings) a few days later," Mr Garcia told Reuters.

"Let's see if the same happens again."

Shares in Mr Slim's mobile phone empire surged by 27% over the second quarter, compared with a 5.7% rise for Microsoft. Mr Slim's bank, Inbursa, also saw its stock jump by 20%.

Mr Gates has headed the Forbes list of the world's wealthiest for more than a decade. But, like Mr Buffett, he is rapidly becoming as well known for giving his money away as he is for accumulating it. Both he and the "Sage of Omaha" have promised to give most of their money to charitable causes.