Since the video tests (vertical vs. square) were identical in content, theme, length, headline, caption, and more, it came as quite the surprise that vertical video outperformed square by such a significant margin (as much as 68 percent less expensive in cost per view).
It’s also interesting to note that not only did vertical video outperform square in the Facebook News Feed, but Facebook outperformed Instagram in overall cost per click (CPC) within the feed