CNNfn Network to Close by Mid-December  NEW YORK (Reuters) - CNNfn, the financial news cable  network owned by Time Warner Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=TWX.N target=/stocks/quickinfo/fullquote"&gt;TWX.N&lt;/A&gt;, on Thursday said it  will cease business operations by mid-December due to the  growing competitive challenges.