(Adds details on Walmex performance)
By Sheky Espejo and Noe Torres
MEXICO CITY, April 5 (Reuters) - Mexico's biggest retailer, Wal-Mart de Mexico, said on Thursday that same-store sales rose in March by the biggest margin in more than 12 years on holiday shopping.
Sales at Mexican stores open for at least a year rose by 13.5 percent from March last year, Walmex said. The growth was the strongest since January 2006, when such data was first available.
Sales rose in the days leading up to Easter Sunday, known as Holy Week, as many people went on vacation. The holiday fell in April last year.
"In addition to the Holy Week holidays, Walmex's sales were supported by the company's promotional campaigns ... which have helped it gain market share," said Marisol Huerta, an analyst at brokerage Multiva.
Total sales in Mexico increased by 15.1 percent on the year.
In Central America, the company controlled by U.S. retailer Walmart Inc posted a 13.9 percent increase in same-store sales.
Walmex said it opened six new stores in the region in March, bringing the total to 3,156 stores at the end of the month.
The company's share price rose 2.3 percent to close at 48.64 pesos on the Mexican stock exchange ahead of the earnings report. (Reporting by Sheky Espejo and Noe Torres; Writing by Julia Love; Editing by Richard Chang)