Spanish banking giant Santander floated its Mexican subsidiary in Mexico and New York on Wednesday in an operation which it said valued the business at $16.54 billion (12.8 billion euros).
The bank's price per share was set at 31.25 pesos ($2.44), making Santander Mexico number 82 worldwide in terms of market capitalisation, a statement from the bank said.
"The value of the transaction will amount to between 2.768 billion euros and 3.183 billion euros," it said, referring to the sum to be raised via the listing.
That would make it "the largest equity offering in Latin America so far in 2012 and one of the largest in the world," Santander said.
The final amount raised would depend on the exercise of a so-called green shoe option, which allows for the sale of additional shares within 30 days if demand is strong.
Santander, the biggest bank in the eurozone by market value, plans to finally retain 24.9 percent of its Mexican subsidiary, the only Mexican financial institution listed in New York.
"This transaction underlines the strength and flexibility of Grupo Santander's model of subsidiaries that are autonomous in liquidity and capital," Santander president Emilio Botin said.
"The IPO (initial public offering) of our unit in Mexico is an important step in our strategy of having market listings for all our significant subsidiaries."
In the first step of the process, 21.7 percent of the capital in Santander Mexico was floated, with 81 percent of that amount listed outside Mexico.
Botin said in early September that he intended to list all of the banking group's major subsidiaries on stock markets within five years.
The Mexican operation should allow the parent group to raise its core capital ratio, a key measure of a bank's ability to withstand financial shocks, by half a percentage point from the level in late June of 10.1 percent.
Maintaining a stronger core Tier 1 capital ratio is a requirement set by international banking authorities following the 2007-2009 financial crisis.