Jaime Aguilera, president of Unilever Spain, was detained in Barcelona, in one of the arrests that took place in six regions around the country, a police source who asked not to be named told AFP.
"He has been detained and released. All of those detained have been released with charges" after questioning and will later be summoned to go before a judge, the source said.
The other suspects included police officers, a tax official, businesspeople and private detectives.
All were charged with "discovering and disclosing secrets", which can mean peddling secret data of public institutions, companies or individuals, and some of them were charged with bribery, the source said, without elaborating.
Unilever Spain could not be reached for comment on late Wednesday. But El Pais newspaper quoted a spokesman for the company as saying Aguilera was cooperating with the investigation.
The arrests were part of an investigation dubbed Operation Pitiusa, launched last year, which Spanish media say has yielded scores of arrests of people suspected of buying and selling secret data.
One of the world's leading suppliers of consumer goods, Anglo-Dutch multinational Unilever owns a wide variety of brands including Knorr, Lipton and Dove.