It was not the best year for Carlos Slim Helú. During 2014 the Mexican telecom mogul went from temporarily reclaiming the world’s richest person title to third place on Forbes World’s Billionaires list.

Over three months, his net worth plunged from a peak of $86.2 billion in September to $71.4 billion last Thursday, a loss of $14.8 billion. He started 2014 with a net worth that Forbes pegged at $73.8 billion.

The drop in Slim’s net worth is linked to weak performance of América Móvil, the flagship telecom company controlled by Slim and his children. América Movil’s shares, which trade on the New York Stock Exchange as well as in Mexico, are down 2.3 percent in dollar terms since January 2, 2014.

Its profit, meanwhile, fell in the July-September period 39.3 percent compared to the period a year earlier as taxes rose and the cost of sales jumped, the company reported. In monetary terms it represented a fall of $10.1 billion pesos ($754 million at the exchange rate at the time) from $16.38 billion pesos a year earlier.

This year Slim held the title of the world’s richest man for five months, beginning when he unseated Microsoft co-founder Bill Gates in July. Between the beginning of June and the middle of September the value of América Móvil’s shares, Slim’s largest holding, rose, helping to push Slim’s net worth to a high for the year of $86.2 billion.

Also in 2014 the process of breaking up his telecom monopoly began. Currently, América Móvil controls 70 percent of all the mobile phones in Mexico, and 80 percent of the country’s landlines.

Early in the year, América Móvil and fellow billionaire Emilio Azcarraga Jean’s TV monopoly Televisa, were declared market dominant in their respective fields by Mexico’s Federal Telecommunications Institute (IFT), a new telecom regulatory agency. The IFT ordered América Móvil to "substantially" cut some of its interconnection rates and forced infrastructure. Starting next year, the company will be forced to cut the rates it charges to complete calls from competing networks.

Slim’s mobile network operator Telcel will only be allowed to charge competing carriers 20 Mexican centavos (about 1 US cent) per minute for incoming calls, down from the current 31 centavos per minute. Bitterly upset, América Móvil said in April: "The referred tariffs in the resolution are comparatively lower than the ones currently in force for the same services in most countries."

In an October report, JP Morgan said that it expects the new business landscape, which will go into full force in 2015, will continue to weigh on América Móvil profit margins in Mexico and Colombia, where its affiliate Claro is the largest provider of mobile phone services in the country.