Shares in Gemstar-TV Guide, the US on-screen television listings group 42%-owned by News Corporation, tumbled over 40% following a ruling by the US International Trade Commission that rejected its bid to enforce its patents against importers of set-top boxes [WAMN: 25-Jun-02].

As a result, NewsCorp is expected to write off an extra $1 billion (€1.02bn; £0.66bn) from its investment in the listings company. Gemstar’s stock has fallen more than 80% since the start of the year, increasing tension between chairman Henry Yuen and Rupert Murdoch.

Yuen vowed to ask the ITC for a review of the ruling.

Data sourced from: Financial Times; additional content by WARC staff