Two weeks ago, around the time Mark Zuckerberg officially eclipsed Warren Buffett as the world’s third-richest person, Facebook seemed practically untouchable. “A reckoning? What reckoning?” one investor asked me, rhetorically. Facebook, after all, had emerged with nary a scratch after a massive privacy scandal involving Cambridge Analytica. On Wednesday, however, the bill appeared to come due. For the first time since 2015, Facebook reported that it had missed revenue projections, and revealed flatlining user growth in North America and the loss of some 3 million daily active users in Europe. Afterward, on a sobering conference call with analysts, Facebook C.F.O. David Wehner said sales growth would continue to slide for the rest of the year. Facebook shares abruptly plummeted as much as 23 percent overnight, erasing about $150 billion in market value.

As Facebook’s stock plummeted, analysts began to ask whether the drop was more than just a correction. “I think many investors are having a hard time reconciling that deceleration,” Brent Thill, an analyst at Jefferies, told Facebook executives on the post-earnings call. “It just seems like the magnitude is beyond anything we’ve seen, especially across a number of the tech (companies) we cover.” Institutional investors were universally bearish the following morning. “New Existential Crisis,” declared Credit Suisse. “Threw out the kitchen sink,” said Jefferies. “Taking a Break from Being Friends,” wrote UBS. To some, this was a sign that Facebook’s once-bulletproof facade had finally begun to crumble in the face of several damning scandals, not to mention the European Union’s implementation of ultra-strict privacy regulation G.D.P.R. Other investors suggested the tech giant’s failure to meet key metrics could be indicative of a deeper fracturing: a longer-term decline for Facebook, and a more permanent disenchantment for Wall Street.

Perhaps Wall Street shouldn’t have been surprised. As one investor told me, Facebook’s slump was largely predictable following its protracted battle to curb fake news—a campaign that Zuckerberg himself had previously warned could hurt profits. “Taking measures to fight misinformation that spreads virally on Facebook’s platform will inevitably work against the company bottom line, because that misinformation drives engagement and growth,” the investor explained. “For now, Facebook can’t have it both ways—crazy growth and a measured approach to fighting the thing that spurs growth on your platform.” In that environment, falling user numbers are natural: “There’s less room for Facebook to grow in its already-established markets.”

Of course, not all analysts were so concerned. “We ultimately believe the advertising revenues and underlying MAU/DAU metrics were ‘good enough’ and show the worries of a massive fundamental and user deterioration at Facebook post Cambridge was more bark than bite,” GBH Insights’s Daniel Ives said in a note. “So far the fundamental damage to the Facebook platform has been very contained in our opinion and is generally better than feared.” Though its losses erased all the gains Facebook made in 2018, Facebook remains insanely profitable and practically unchallenged as the world’s pre-eminent social network. For comparison’s sake, the company lost $134 billion in the immediate wake of the Cambridge Analytica scandal and recovered within two months. Perhaps in an effort to mitigate the company’s losses, Zuckerberg shared a new metric on Wednesday’s earnings call: 2.5 billion, the number of people who use at least one of Facebook’s apps, including WhatsApp, and Instagram.

Perhaps the more chilling portent, in retrospect, is that Facebook has been laying the groundwork for a turndown since last year. Zuckerberg, who lost around $16 billion in the crash, has long held that short-term Wall Street incentives are not aligned with Facebook’s healthy long-term growth. On past earnings calls, he’s said that as Facebook shifts News Feed toward posts from family and friends and spends on efforts to ramp up content moderation, the company’s bottom line would take a hit. If sluggish numbers were the price of regaining users’ trust, he seemed to suggest, so be it. “Facebook, and particularly Wehner and Zuckerberg, have warned for quarters now that a slowdown would eventually come,” another investor told me. “There’s a limit to how many people you can sign up for Facebook accounts. That it took this long for Wall Street to notice is more of an indictment of them than of the company.”