Was it a Donald Trump bump?
The audience for Saturday's Republican debate, shown on ABC, was 13.18 million, a jump perhaps attributable to the real estate mogul and reality TV personality returning to the debate stage with the other Republican presidential contenders.
Trump passed on that gathering because he was still steamed over the tough questions that Fox News anchor Megyn Kelly asked him in the first debate on Aug. 6. He held a competing event to raise money for veterans groups.
But Trump finished second in the Iowa caucuses behind Sen. Ted Cruz after leading in polls. He acknowledged that his absence from the debate may have disappointed some caucus-goers and hurt his showing.
The viewership jump showed that people will tune in to a debate on a Saturday - the night of the week that typically has the lowest number of homes using television.
The Democratic National Committee has been criticized for scheduling debates on Saturdays. ABC's last debate, when the Democrats met in New Hampshire on Dec. 15, was watched by 8.03 million viewers. When the Democrats faced off Nov. 14 on CBS, 8.55 million watched.
But the Republicans have drawn larger numbers throughout the campaign season going back to Aug. 6, when Fox News' audience of 24 million set a cable ratings record for a non-sports program.
Saturday's debate, moderated by "ABC World News Tonight" anchor David Muir and "This Week With George Stephanopoulos" co-anchor Martha Raddatz, had the largest audience for a primary debate shown on a broadcast network in at least 20 years.
The previous high was ABC's telecast of the Democratic primary debate on April 16, 2008, which had an average audience of 10.6 million viewers.