How Facebook’s $120 billion loss ranks among the biggest one-day stock disasters

At market close Wednesday, Facebook Inc. was worth $630 billion.

One day later: $510 billion.

That roughly $120 billion loss in market cap tops the list of biggest one-day routs in recent stock market history — and by a very wide, $30-billion margin.

Facebook stock FB, -18.96%   ended down 19% on Thursday, its ugliest single-session decline since it became a publicly traded entity on May 18, 2012. According to WSJ Market Data, Facebook’s drop is the biggest one-day loss in history among the current top 25 companies by market cap and some other notables.

Some more perspective on just how huge a number $120 billion is (in case you need that): The drop is larger than the individual market caps of 464 of the 500 companies in the S&P 500, or 92.8% of them. And if you were to add up the market caps of the bottom 21 companies in the S&P 500, it’s bigger than that, too.

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The stock to come closest to Facebook’s nightmare day was Intel on Sept. 22, 2000, during the fallout of the dot-com bust. Intel INTC, -0.51%   lost $91 billion that day, with the stock tumbling 22%, after it revealed weakening demand in Europe and projected revenue growth far below what analysts were expecting.

Next up on the disaster hit list is Microsoft’s MSFT, -1.09%   $80 billion drop on April 3, 2000, also in the days of the dot-com fallout. Then comes Apple’s AAPL, -0.31%   January 2013 drop, when lackluster earnings results and a slew of analyst price-target cuts caused it to shed nearly $60 billion in market cap in one day — and lose its title of world’s most valuable company.

But by the end of 2013, Apple’s market cap was back above its level before that massive one-day drop and, of course, it has long since regained the title of most valuable company (Amazon’s recent surge notwithstanding) — some history that Facebook investors may want to keep in mind in the months ahead.