Investors were calmed by the ruling party's win, coming at the end of eight months of political turmoil that began with an Indian uprising in the impoverished southern state of Chiapas and was heightened by the March assassination of the leading presidential candidate.
Despite reports of irregularities, Mr. Zedillo came out victorious and the ruling Institutional Revolutionary Party will continue to dominate Congress.
Mr. Zedillo is expected to deepen the current government's free-market reforms, highlighted by the North American Free Trade Agreement.
"The result means continued confidence in the system," said Liz Paul, regional director in charge of multinationals at J. Walter Thompson Mexico.
Mr. Zedillo's first priority will be to restore economic growth. Despite the reforms instituted by President Carlos Salinas de Gortari, most Mexicans' purchasing power is virtually the same as 1980, before the lean debt-crisis years.
For that reason, multinationals may delay introducing new lines and products. In the past five years, Mexicans have been inundated with fresh products as the economy opened to imports and marketers expanded their offerings.
"Until Mexican consumer buying power catches up with the options, there won't be any major rush into the market for a while," Ms. Paul said.