Shares in the Mexican unit of Spain\'s Banco Santander rose on their first day of trading in Mexico City and New York on Wednesday, the biggest operation of this type in Latin America this year. The Spanish banking giant said the operation would raise between 2.77 billion and 3.18 billion euros ($3.57 billion and $4.1 billion). \"It is the biggest share offering in Latin America in 2012 and one of the largest in the world,\" the bank said in a statement. The shares in Grupo Financiero Santander Mexico were initially priced at 31.25 pesos ($2.44), valuing the business at $16.54 billion. They closed at 33.33 pesos in the Mexico City stock exchange, more than six percent over the initial price. On Wall Street, Santander Mexico finished the day 2.46 percent higher at $12.91. \"It was a successful offering with a lot of demand,\" Rodrigo Heredia, an analyst at broker Ve, told AFP. The Mexican bank has almost 10 million clients and is Banco Santander\'s third biggest unit after Brazil and Britain.