Santander Mexico Shares Rise on First Trading Day Shares in the Mexican unit of Banco Santander rose strongly on the New York and Mexico City exchanges a day after their public offering, a showing widely seen as a sign of confidence in the Mexican economy. The price of stock in Grupo Financiero Santander Mexico was up more than 5 percent on the Mexican exchange around midday Wednesday, and nearly 9 percent on the New York Stock Exchange. The Spanish bank sold nearly a quarter of Grupo Financiero Santander Mexico's share capital as what it called part of a strategy of listing the bank's most important subsidiaries within five years and boosting growth. The bank said the offering was the largest equity transaction in Latin America this year.