The suit's main complaint alleges Thomson used confidential information gained at CCBN board meetings to compete against the company.
In a statement, Thomson said: 'Thomson categorically denies the allegations and intends to vigorously defend itself against this baseless claim.'
Thomson holds two seats on CCBN's board of directors as a result of its ten per cent stake in the firm.
In recent months, both of Thomson's directors have quit but the company is yet to relinquish its right to the directorships.
CCBN seeks financial damages and restrictions on Thomson's ability to compete with it.