Anti-trust watchdog CNMC has launched a probe into suspected collusion in manufacturing, distribution and marketing of tobacco products by Spanish subsidiaries of four big international tobacco companies, Reuters said.

Philip Morris Spain, Altadis, JT International Iberia, British American Tobacco Espana and Compania de Distribucion Integral Logista are targets of the investigation, the news agency said, citing CNMC. Investigators made surprise inspections at the offices of the tobacco companies earlier this year, and could take up to 18 months to deliver a finding, Reuters said.