Twitter has been a boon for Hollywood — if we believe a Twitter-commissioned study by MarketShare on tweets and ticket sales, that is. According to that study, Twitter helped to sell almost one in 10 tickets in North America over the last four years.

The uplift was especially notable for action movies: Twitter contributed to 13 percent of all action movie ticket sales in the U.S., and to 9.6 percent of comedy movie sales. Across North America, it helped to sell 8.9 percent of all movie tickets, according to the study.

This was in part due to Hollywood spending ad dollars on Twitter, but also due to actors, fans and studios tweeting about movies. Twitter tracked more than 165 million movie-related tweets worldwide in 2015 alone.

Of course, it’s no surprise that Twitter would commission and highlight research that aims to show how well its ads are working. To that end, the study also claims that Hollywood studios can get more bang for their buck out of TV ad campaigns if they combine them with Twitter ads.

Across North America, studios see a 16 percent higher return-on-investment for TV ads promoting their movies if they combine them with Twitter ads, according to the study. MarketShare conducted the study based on Twitter and box office data from December 2011 to June 2015.

But while Twitter may be good at helping studios to drive ticket sales, it hasn’t actually proven to be a good platform for any kind of movie merchandise commerce. Twitter started to test a buy button for on-platform commerce in 2014, and rolled out product pages with partners like Disney, Fox and HBO a year ago. However, the exec in charge of that initiative has since left the company, and development of these initiatives has ceased, according to BuzzFeed.