National TV advertising minutes per hour grew sharply by 6% in the second quarter this year over the year before --- the sharpest quarterly spike in years.

Surveying eight major TV network groups -- and independents -- showed TV commercials' minutes per hour across total day viewing was at 13.3 minutes per hour versus 12.6 minutes in the second quarter of 2020, according to analysis from MoffettNathanson Research.

Some of this was due to “a more normalized schedule,” says the report -- coming out of the COVID-19 pandemic period where advertisers were cancelling or shifting media buys to other periods. But the report says long-term, systemic low viewership issues were also a factor.

In the second quarter of 2020, there was a 2% decline in total day commercial minutes per hour. Previously, significant growth came in the third quarter of 2015 and the second quarter of 2018, each rising 3%.

Discovery Inc. showed the biggest growth 16% year-over-year to average 13.7 minutes. Independent network groups grew 8.5% to 13.6 minutes.

The two TV networks with the most average commercial minutes were A+E Networks (14.7 minutes) and ViacomCBS (14.3 minutes) -- up 4.7% and 7.7%, respectively.

MoffettNathanson says that ViacomCBS has recently been making progress. Prior to the second-quarter 2021 period, Viacom posted a series of declines in the average number of commercial minutes for a number of quarterly periods. Then in the second three months of this year, it witnessed a spike in commercials minutes.

Coming in with the lowest commercial minutes per hour was Walt Disney networks, at 11.7 -- up just 3.3% from the year before.