Facebook changes its News Feed algorithm all the time, but Thursday’s big update is not like the others.
You can tell by the spike in the amount of stock trading hands. More than 69 million shares of Facebook stock have been traded today — the highest volume day in the past year.
Mark Zuckerberg announced yesterday that the social media site would prioritize posts from friends and family and reduce the reach for brands and publishers, presumably hurting their referral traffic. Altogether that means less time spent on Facebook, Zuckerberg said.
Investors weren’t very happy about that. Facebook’s stock dropped 5 percent this morning.
Other big trading days, unsurprisingly, followed Facebook’s regular earnings releases where the company gives a slew of updates, including its financials. This news was bigger than all of those updates based on trading volume.
Facebook has made plenty of changes to News Feed over the years, but they haven’t caused as much mayhem.
For comparison, after Facebook announced a similar move to favor user-generated content in 2016, about 20 million shares traded hands — a third of what was traded today. On average, 15 million shares are traded each day.
This article originally appeared on Recode.net.