MADRID, June 7 (Reuters) - Spain's CaixaBank has sold a 3.7 percent stake in Carlos Slim's Grupo Financiero Inbursa for 387 million euros ($511 million) to the Mexican billionaire's family, part of a move to shed assets and shore up capital.
The Barcelona-based lender is set to raise just over 1 billion euros from cutting its Inbursa holding by just over half to at most 9.9 percent of the total.
It said on Friday it had sold 3.7 percent of Inbursa to Inmobiliaria Carso, owned by the Slim family, and planned to sell another 6.4 percent in tranches for Mexican and international investors, leaving it with a stake of 9.0 to 9.9 percent.
CaixaBank last month announced the plan to cut the stake as it attempts to strengthen its capital base.
It will make a capital gain of 33 million euros.
The first tranche was sold at 26 pesos per share versus Inbursa's closing price of 29.580 pesos. Slim's family had the first option to buy the shares, according to the terms of CaixaBank's 1.5 billion euro purchase of the stake in 2008.
Slim was ranked as the world's richest person last year with a $73 billion fortune, according to Forbes magazine.
The purchase should take the holding of the family in Inbursa up to almost 60 percent.
Juan Pablo Lopez, analyst at Espirito Santo, said the sale was positive and the transactions should boost core capital at CaixaBank by about 120 basis points under full Basel III rules, lifting it to about 8.9 percent.
He estimated that if the bank invests the proceeds at a 5 percent yield, the sale would have a negative impact of 30 million euros on profits next year.
CaixaBank is looking to sell at least some of its corporate holdings as stricter international rules on capital levels make it more expensive to hold them.
It has stakes in Spanish companies such as Telefonica , Repsol and Gas Natural.