New Zealand's two biggest print and online media companies, NZME and Fairfax, will not be allowed to merge.
The media giants failed in their legal bid to overturn a Commerce Commission decision blocking them from joining forces.
The High Court released its decision on Tuesday morning, saying the appeal had been declined.
The court said it had "upheld the jurisdiction of the commission to consider detriments beyond economic or financial detriments in the relevant markets".
NZME owns The New Zealand Herald and many regional papers as well as a large number of commercial radio brands including Newstalk ZB, The Hits and ZM.
Fairfax owns Stuff.co.nz as well as regional papers like The Dominion Post, The Press and The Timaru Herald.
More to come