(Bloomberg News) The 100 wealthiest people on the planet dropped $4.2 billion from their collective net worth this week after Hurricane Sandy halted trading in the U.S. for two days.

Mexican Carlos Slim, 72, lost $2.9 billion after the Colombian government announced Thursday that his Mexico City-based telecommunications company, America Movil SAB, will be partially excluded in an auction of licenses for 4G airwaves next year. Slim remains the world's richest person with a $74.7 billion fortune, according to the Bloomberg Billionaires Index.

"The main impact was the shutdown of the exchange for two days," said Walter "Bucky" Hellwig, who helps manage $17 billion at BB&T Wealth Management in Birmingham, Alabama. "The first day the exchange was open the phones were still down up there."

NYSE Euronext shut markets across every asset class on Monday and Tuesday, the first consecutive closures because of weather since 1888, as Sandy barreled into the East Coast. Nasdaq OMX Group Inc. and all other U.S. equity markets also shut down. The U.S. Labor Department yesterday presented its last jobs before next week's presidential election. A net 171,000 workers were added to payrolls in October, according to the report.

The Standard & Poor's 500 Index gained 0.16 percent during the week to close at 1414.20 in New York. The Stoxx Europe 600 Index rose 1.6 percent, closing at 274.85.

Buffett, Mikhelson

Microsoft Corp. co-founder Bill Gates, 57, is the worlds's second-richest person with $63.3 billion. Europe's richest man, Amancio Ortega, the 76-year-old founder of Inditex SA, the world's biggest clothing retailer and owner of the Zara clothing chain, is No. 3 on the index with a net worth of $54.1 billion, $7.5 billion ahead of Warren Buffett, 82.

Buffett's Omaha, Nebraska-based, Berkshire Hathaway Inc. agreed yesterday to buy closely held Oriental Trading Co., the U.S. direct retailer of party and craft supplies based in the same city as Berkshire, for about $500 million.

Leonid Mikhelson, the billionaire who controls Tarko-Sale, Siberia-based OAO Novatek, Russia's largest private gas producer, lost a 25-year contract to supply natural gas to state-run OAO Inter RAO UES's power plants to OAO Rosneft, Russia's biggest oil producer. The 57-year-old lost $1.3 billion as Novatek shares were down almost 10 percent for the week in London trading. He ranks 45th on the list with a net worth of $15.8 billion.

The Bloomberg Billionaires Index takes measure of the world's wealthiest people based on market and economic changes and Bloomberg News reporting. Each net worth figure is updated every business day at 5:30 p.m. in New York. The valuations are listed in U.S. dollars.