Mark Zuckerberg’s latest Facebook post is proving expensive.

The co-founder of the world’s largest social-media business saw his fortune fall $2.9 billion Friday after he posted plans to shift users’ news feeds toward content from family and friends at the expense of material from media outlets and businesses.

Shares of Menlo Park, California-based Facebook tumbled 3.9 percent at noon in New York, cutting Zuckerberg’s fortune to $74.4 billion on the Bloomberg Billionaires Index. If that decline holds through the close of trading, he will lose his place as the world’s fourth-richest person to Spanish retail billionaire Amancio Ortega.

The drop wipes out much of the $4.5 billion Zuckerberg, 33, has added so far this year. The world’s 500 richest people gained $1 trillion in 2017 and an additional $17 billion in the first two weeks of 2018, according to the Bloomberg index.