In a move that flips conventional media wisdom on its head, streaming portal Roku says it will guarantee that advertisers can reach bigger audiences in primetime than some of the company’s traditional cable rivals.

“TV streaming has long brought precision and measurement to the largest screen in the home,” says Kristina Shepard, Roku’s co-head of U.S. brand sales, in a prepared statement. “Now, marketers can launch campaigns knowing they will deliver meaningful reach and impact quickly, too.” Roku has 70 million active accounts.

Though the advent of streaming has given consumers the ability to choose when they want to watch their video favorites, the hours of 8 p.m. to 11 p.m., still known as “primetime” in the TV industry remain a choice period to reach potential customers. These hours are viewed as a block when consumers are no longer occupied by work and in a relaxed state — open, so the thinking goes, to commercial pitches. In a different era, they could be reached easily by traditional commercials via broadcast and cable. Increasingly, however, they can now be found hunting for something good to stream at moments of their own determination.

To be sure, Roku will beam ads to a disparate crowd, not a unified one. Traditional TV programming retains appeal because it reaches large simultaneous audiences all gathered to watch a single piece of content. That continues to attract big advertisers, who seek efficiency as well as big consumer crowds.

Popular on Variety

Roku makes its offer as the media sector prepares for its annual “upfront” market, where U.S. TV networks try to sell the bulk of their advertising inventory for the next programming cycle. Roku isn’t always considered the biggest player in such discussions, but one media buying executive notes that advertisers could seek to do a big deal with a non-traditional player like Roku or Amazon this year, given their significant connection with consumer households.

Under the new Roku offering, advertisers would choose a specific date for commercials to run. Roku would make delivery of those ads across its Roku Channel and 100 top channels on its platform a priority. Just as local cable systems get two minutes of time to run commercials each hour, Roku also gets a certain amount of inventory it can run in various streaming counterparts. The difference: Roku can send specific ads to individual households based on data and interactive technology.

Roku says a pilot program utilizing the primetime guarantee done in conjunction with a financial-services advertiser reached more TV households between 8 p.m. and 11 p.m. than an average program on a top-five cable network. Roku found that total household reach was 15% greater.

VIP+ Analysis: Why Digital Advertising Steals TV’s Thunder