Slim has a substantial influence over the telecommunications industry in Mexico and much of Latin America as well. He controls Teléfonos de México (Telmex), Telcel and América Móvil companies. Though he maintains an active involvement in his companies, his three sons Carlos Slim Domit, Marco Antonio Slim Domit and Patrick Slim Domit head them on a day-to-day basis.
Slim is the surname of Carlos' father Julián, who was called Youssef Salim before moving to Mexico, upon which he changed his first name to Julián and altered his surname to Slim. He officially became Julián Slim Haddad by adding Haddad, his mother's surname, according to the Spanish-language naming customs. In Western, non-Iberian naming conventions, Carlos Slim Helú's name would be Carlos Slim.
Slim studied engineering at the Universidad Nacional Autónoma de México. He married Soumaya Domit in 1967; the couple had six children and were married for 32 years until Domit died of a kidney ailment in 1999.
Like his family, Carlos Slim Helu is a Maronite Catholic. He is thought to be close on a deal to secure English football club Portsmouth.
On August 8 2007, Fortune magazine reported that Slim had overtaken Bill Gates as the world's richest man. Slim's estimated fortune soared to US$68 billion, based on the value of his public holdings at the end of July. Microsoft founder Bill Gates' net worth was estimated to be at least US$58 billion.
On August 4, 2007, The Wall Street Journal ran a cover story profiling Slim. The article said, "While the market value of his stake in publicly traded companies could decline at any time, at the moment he is probably wealthier than Bill Gates". On March 29 2007, Slim surpassed Warren Buffett as the world's second richest person with an estimated Net Worth of US$53.1 billion compared to Buffett's US$52.4 billion. According to The Wall Street Journal, Slim credits part of his ability to discover investment opportunities early to the writings of his friend, futurist author Alvin Toffler.
He was on the Board of Directors of the Altria (Previously Philip Morris) Group (resigned in April, 2006) and Alcatel. He was on the Board of Directors of SBC Communications until July 2004 to devote more time to the World Education & Development Fund, which focused on infrastructure, health and education projects. In 1997, just before the company introduced its famous iMac line, Slim bought 3% of Apple Computer's stock, which has skyrocketed over the years.
He built an important Mexican financial-industrial empire, Grupo Carso, which owns, among other companies, the now bankrupt CompUSA electronic retail chain. On December 8 2007, Grupo Carso announced that the remaining 103 CompUSA stores would be either liquidated or sold, bringing an end to the struggling company. After 28 years he became the Honorary Lifetime Chairman of the business. He is also Chairman of Teléfonos de Mexico, América Móvil, and Grupo Financiero Inbursa.
Slim was once MCI's largest shareholder, with 13% ownership. On April 11 2005, The Wall Street Journal announced that he had sold his stake in MCI to Verizon Communications of the United States.
On 10 September 2008 Slim announced that he had purchased a 6.4% common-stock stake in The New York Times Company, making him the largest shareholder not related to the company's owners, the Sulzberger family.
In the year 2000, Slim organized the Fundación del Centro Histórico de la Ciudad de México A.C. (Mexico City Historic Downtown Foundation), whose objective is to revitalize and rescue Mexico City's historic downtown to enable more people to live, work and find entertainment in this area. He has been Chairman of the Executive Committee for the Restoration of the Historic Center since the year 2001. Additionally, as part of his philanthropic work, he heads the Latin America Development Fund project, and his foundations have more than 10 billion dollars budget for the next years.