BSkyB has been ordered by a court to sell offload some of its 17.9 per cent stake in ITV.
The broadcaster lost its appeal and was told to reduce its stake to below 7.5 per cent.
BSkyB bought into the company for £940m in 2006 – effectively blocking cable group NTL from buying ITV.
However, the broadcaster claims it was an investment and not intended to stifle competition.
BSkyB has previously argued that it is not breaking UK media ownership laws because the stake is less than 20 per cent.
It has fought to retain its stake since the Competition Commission decided in late 2007 that the purchase could be against the public interest.
Business secretary John Denham upheld the decision the following month, and the Competition Appeal Tribunal also backed the decision in September 2008.
In March 2009 the case went to the Court of Appeal for hearing, leading to the latest court decision.
The broadcaster can still appeal to the Supreme Court over the ruling.