Mark Zuckerberg could be ending the year about three-fourths as rich as he was coming into it.

Mired in controversy throughout the year, Zuckerberg’s net worth started at around $75 billion on January 2, and he’s set to finish at least $15 billion less when the year comes to a close — a greater loss than any of the other 499richest people in the world.

The Facebook founder’s 13% stake in the company makes up almost all of his fortune. Accusations of the platform’s role in Russian election interference and the mass genocide in Rohingya put a closer eye on Facebook, and the unraveling revelations of data breaches and unsavory practices at the executive level that followed led to a number of stock price drops. As the person holding the reins for the entire operation, Zuckerberg has been held accountable personally and — as the chart below shows — financially.

It goes without saying that his accountant probably isn’t too worried about his declining fortune, which also includes $2.4 billion in “cash and other assets” and $175 million in real estate according to Bloomberg. But the events of 2018 have done the unprecedented for Zuckerberg: his net worth backtracked to where it was almost two years ago.

Here are the events of 2018 that brought Zuckerberg’s total net worth down.

Cambridge Analytica

On a Saturday in March, Cambridge Analytica co-founder and former director of research Christopher Wylie threw Zuckerberg for a loop when he came forward to say the data analytics company had misused 50 million Facebook users’ data. Hired by the Trump presidential campaign to handle its targeted digital advertising for the 2016 primaries, Cambridge Analytica used the unauthorized Facebook data to target voters.

Wylie told The Guardian that Facebook knew Cambridge Analytica had the data back in 2015, but didn’t do enough to make sure Cambridge Analytica deleted it. Users were outraged at what they considered Facebook’s carelessness.

On Monday, March 19, Facebook’s stock price closed 7% lower ($173) than it closed on the Friday before and Zuckerberg lost $5 billion on that day. It continued spiraling until March 27, when it was down 18% to $152. At that point, Zuckerberg had lost a little over $13 billion.

The number of affected users was revealed to be more like 87 million on April 4 but the market didn’t seem to mind. Zuckerberg’s net worth returned diligently to its pre-scandal $75 billion by May 9.

Reacting to chaos

Market dips and earnings results affected Zuckerberg’s net worth like they always do, but this year marked some abnormalities.

Facebook suffered the worst single-day loss in the history of the U.S. stock market on July 26, after releasing its Q2 earnings report after trading hours on July 25. Facebook’s stock was at its all-time high ($217.50) when the market closed, and opened 20% lower the next day. By the end of July 26, Zuckerberg had lost $15.9 billion and another $2.2 billion in the days that followed. This time he didn’t get it back.

What happened? The first full quarter after the scandal was met with decent profits, but sales looked bleak, user growth abroad was suffering, and executives didn’t exactly soothe investors with their words. “We’re investing so much in security that it will significantly impact [Facebook’s] profitability,” Zuckerberg said during the earnings call.

Facebook had a new low on Oct. 29, the eve of Facebook’s Q3 earnings results, at which point Zuckerberg’s net worth was down 24.4% from the beginning of the year. These earnings results were less than impressive, but did enough to bring him out of that rut — temporarily.

Facebook Unfriended

All of the remaining co-founders of Facebook-acquired WhatsApp and Instagram called it quits in 2018, allegedly for Facebook’s inability to play well with others.

WhatsApp co-founder and CEO Jan Koum announced he was leaving on April 30, reportedly unable to agree with Facebook on how it wanted to handle its data. And about five months later, Instagram co-founders Kevin Systrom and Mike Krieger left without giving any reason, although it was reportedly due to mounting tensions.

Two days after Systrom and Krieger left, Forbes published an interviewinterview with WhatsApp’s co-founder Brian Acton that painted Facebook’s executives in a rather disagreeable light. Acton — whose last tweet following the Cambridge Analytica scandal reads as anti-Facebook as it gets — explained that he left a year earlier for moral reasons and described the unpleasant departure that followed.

A day after the interview came out, Zuckerberg started losing a couple of billions and the S&P’s subsequent dip brought the total to $6 billion in two weeks. His net worth was now down to where it was at the lowest point following the Cambridge Analytica scandal.

Any small gains were quickly erased over election week, and erased twice over following a New York Times story on November 14. In it, the Times reported that Zuckerberg and COO Sheryl Sandberg ignored warnings and hid evidence about Russian interference, and downplayed the Cambridge Analytica scandal when confronted about it. Sandberg was also caught in a web of her own liesafter denying any involvement in hiring the firm aimed at making a scapegoat out of liberal investor and philanthropist George Soros.

By market close on November 19, at the lowest Zuckerberg’s fortune had been in almost 100 weeks, his net worth was down 30% from the first trading day of the year.

What happens to Facebook and to Mark Zuckerberg’s fortune in 2019 depends a lot on what lawmakers decide to do with the company and any regulations surrounding the larger tech community. The only real light at the end of the tunnel for his net worth is that analysts are betting that it can’t get much worse than 2018.

Still, Zuckerberg is a multi-billionaire by a long shot. He joined the Forbes’ World’s Billionaires List in 2008 and has been sitting pretty in the Top 10 on both Forbes’ list and the Bloomberg Billionaire Index for years. Even at the end of an objectively bad year, he’s the No. 5 breadwinner in the world; if he were a company in the S&P 500, he would be the 120th richest.