Criteria CaixaCorp, the investment company owned by Spain's biggest savings bank La Caixa, agreed to buy 20 per cent of Carlos Slim Helu's Grupo Financiero Inbursa SA for €1.5 billion ($2.4 billion) to tap economic growth in Mexico.

Criteria will pay 38.5 pesos ($3.71) a share for the holding, as it takes part in a bigger stock sale by Mexico City-based Inbursa, the Spanish company said today in a filing. The offer represents a premium of 8.6 per cent on the 23rd May closing price.

Criteria said it would use debt to buy its first major investment in Latin America.

Inbursa shares gained 7.13 per cent to 37.99 pesos amid low trading volume as US and British markets were closed for holidays. Criteria rose 6 cents, or 1.4 per cent, to €4.30 in early Madrid trading.

Criteria, which holds the financial and industrial holdings of Spanish bank La Caixa worth around €24 billion is looking to diversify into another Spanish-speaking country even as it faces tough times at home, with Spain increasingly looking towards a recession.

With this latest move, it joins peers like Banco Santander SA and Banco Bilbao Vizcaya Argentaria SA in investing in Mexico, as more workers in the country are escaping poverty and using financial services. Mexico's economy will grow an average 2.8 per cent in 2008 and 2009, as compared to Spain's 2.2 per cent. Moreover, the latter's economy grew by only 0.3 per cent in the first quarter, the slowest pace in almost 13 years.

Inbursa, which has a major insurance business, has more than 6.7 million customers, 5,000 employees, more than $170 billion under management and made a net profit of $497 million last year, Criteria said. The Inbursa stake will also become a vehicle for expansion in the Americas, it added, without giving further details. The unit is seeking to invest in Asia and central and Eastern Europe as well as in Spanish-speaking countries.

Criteria will be able to name two Inbursa board members under the deal, while the Slim family ''will keep the majority of the capital and the management,'' as per the filing. Criteria's other recent investments include buying 5 per cent of exchange operator Bolsasy Mercados Espanoles and increasing its holding in highway operator Abertis Infraestructuras SA.

The deal is ''beneficial for both sides and from Criteria's point of view it will constitute a fundamental pillar in its international expansion,'' Ricardo Fornesa, Criteria's chairman, said in a statement.

Carlos Slim Helu, born 28 January 1940, is a Mexican businessman largely focused on the telecommunications industry. He is the second richest man in the world with a net worth of around $60 billion through his holdings.

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. He is also chairman of Inbursa, on of the top ten banks in Mexico.

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. Marco is CEO of Inbursa.