Bill Gates
Bill Gates is the world's richest man with a net worth of .5bn. Reuters

The world's 300 richest people added more than half a trillion dollars to their collective net worth in 2013, according to an index compiled by Bloomberg.

The billionaires had a collective net worth of $3.7tn (£2.2tn, €2.7tn) at the market close on 31 December, up $524bn from the previous year, according to the Bloomberg Billionaires Index.

Of the 300 billionaires on the index, only 70 registered a net loss for the year 2013.

Stock markets across the world have fared well in 2013, as major economies showed signs of coming out of the pains of the global financial crisis.

The MSCI World Index rose 24% during the year to close at 1,661.07 on 31 December, the highest gain since 2009. In addition, companies in the S&P 500 list are worth $3.7tn more today than they were 12 months ago.

Among sectors, technology yielded more gains for the 12-month period, rising 28% during the year.

Bill Gates, Biggest Gainer of 2013

The year's biggest gainer was 58-year-old Bill Gates, the founder and chairman of Washington-based Microsoft. His fortune increased by $15.8bn to $78.5bn in 2013 to beat Mexican tycoon Carlos Slim as the richest man on the planet.

Shares in Microsoft, the world's largest software maker, rose 40% during the year. Gates holds a 4.8% stake in Microsoft, representing about a fifth of his total wealth.

The rest of his fortune lies in closely held Cascade Investment, a holding company that was created with the proceeds of Microsoft stock sales and dividends.

Cascade has holdings in about three dozen public companies, including AutoNation, Canadian National Railway and Strategic Hotels & Resorts. Gates also has investments in Four Seasons Hotels, photography company Corbis Images and energy firm Sapphire Energy through the entity.

He has also donated $28bn to the Bill & Melinda Gates Foundation.

Apart from Microsoft, Gates mostly benefited in 2013 from a rally in stock holdings in Canadian National Railway Co. and sanitising-products maker Ecolab Inc., which rose 34% and 45%, respectively.

Notable Gains and Losses

Sheldon Adelson, founder of casino operator Las Vegas Sands Corp., was the second biggest gainer in 2013, adding $14.4bn to his wealth. Las Vegas Sands shares rose 71% during the year, as revenues from Macau surged.

Slim lost $1.4bn during 2013 and his net worth stands at $72bn at present. Shares in his America Movil, the largest mobile-phone operator in the Americas, fell 12% in the first three months of the year after the Mexican government passed a bill to quash the billionaire's market dominance.

Eike Batista, the owner of Brazilian oil company OGX Petroleo & Gas Participacoes, was the biggest loser in 2013, with his net worth declining more than $12bn. His company filed for bankruptcy in October, and he has a negative net worth according to the Bloomberg index.

The fortunes of Google founders Larry Page and Sergey Brin surged about $10bn each as the search-engine achieved significant growth.

Macau casino mogul Lui Che Woo added $14.2bn to his net worth to become the biggest gainer in Asia.

Li Ka-Shing remains Asia's richest man with a fortune of $30.2bn, while Amancio Ortega held the position in Europe.

Saudi billionaire Prince Alwaleed bin Talal remained the Middle East's wealthiest person and Aliko Dangote is the richest person in Africa.