News Corp. (NWSA)’s Fox News led cable networks in last night’s debate between President Barack Obama and Republican challenger Mitt Romney with 10.4 million viewers.

Time Warner Inc. (TWC)’s CNN was second with 6.05 million viewers and Comcast Corp. (CMCSA)’s MSNBC was third with 4.71 million, according to Nielsen data released today by Atlanta-based CNN. Nielsen plans to release detailed results later today, including the ratings of major broadcast networks.

Last night’s face-off, held at the University of Denver and moderated by PBS’s Jim Lehrer, was the first of three presidential debates before the Nov. 4 general election. The Fox channel, the most-watched cable news network, held its ratings edge through the evening, averaging 6.45 million viewers from 7 p.m. to midnight, the data show. CNN drew 3.72 million during that period, with MSNBC attracting 3.1 million.

News Corp., controlled by Chairman and Chief Executive Officer Rupert Murdoch, gained 0.9 percent to $24.98 at 3:19 p.m. in New York. The Class A stock (NWSA) had climbed 39 percent this year as of yesterday.

To contact the reporter on this story: Andy Fixmer in Los Angeles at afixmer@bloomberg.net

To contact the editor responsible for this story: Anthony Palazzo at apalazzo@bloomberg.net