The European Securities and Markets Authority (ESMA) said on Thursday that, between June 2013 and April 2018, 20 percent of Fitch subsidiaries in Britain, France and Spain were indirectly owned by an individual through an entity in France.

At the same time the shareholder, which ESMA does not name, was sitting on boards of three entities being rated by the three subsidiaries of Fitch, the bloc's third biggest rating agency.

Fitch said none of the breaches impacted the outcome of its ratings, and its interpretation of the EU regulations on disclosing the identity of shareholders was made in good faith.

"We no longer have single individual shareholders who may be in a position to sit on the boards of rated entities," Fitch said in a statement.

Fitch is owned by U.S. publisher Hearst after buying stakes from France's Fimalac. It is one of the "Big Three" credit rating agencies, along with Standard & Poor's and Moody's that dominate the sector globally.

ESMA authorizes and regulates ratings agencies in the EU. It said its fine reflects measures voluntarily taken by the three Fitch subsidiaries to ensure similar infringements could not be committed in the future.

Fitch accounts for 15.1 percent of the EU's market for credit ratings, third after S&P with 46.3 percent and Moody's with 32 percent.

ESMA fined Fitch 1.4 million euros in July 2016 after finding that some senior analysts at the agency transmitted information about some sovereign ratings to senior people in a Fitch parent company before it was made public.

($1 = 0.8882 euros)

(Reporting by Huw Jones; Editing by Mark Potter and Robin Pomeroy)

By Huw Jones