Google plummeted almost $80 per share, more than 10 percent, and trading in the stock was halted two and a half hours Thursday after a disappointing earnings report was published ahead of schedule and surprised investors.
Bleak figures in the report about online advertising dragged down Facebookstock, too, and the Nasdaq composite index skidded 1 percent on a day when the broader stock market was mostly flat.
Google was trading at $754 per share at 12:30 p.m. EDT, then fell almost $20 in a minute after investors saw the report, a draft. It dropped as low as $676, and Google halted trading at 12:50 p.m., with the stock at $687.
The stock was halted until 3:20 p.m. Companies routinely halt trading when they have news to release to investors during the market day, but two and a half hours is an unusually long suspension.
When trading in Google resumed, the stock climbed slightly, but it still finished down $60.49, or 8 percent, at $695.
R.R. Donnelley & Sons stock also plunged — as much as 71 cents, or 6.5 percent, to $10.14 — after the mistake. It later recovered most of the loss and ended the day down 9 cents.
The Google report said it earned $2.18 billion from July through September, down from $2.73 billion in the same period a year ago.
Profit came to $6.53 per share, and would have been $9.03 if not for accounting costs from employee stock compensation and restructuring charges related to Google's acquisition of Motorola Mobility, a cellphone maker.
Still, analysts polled by FactSet, a provider of financial data, were expecting $10.63 per share.
Besides disappointing investors, the report was an embarrassment for Google. Near the top of the draft, the report said, "PENDING LARRY QUOTE," apparently a place to insert a quote from Larry Page, one of Google's founders.
The earnings report said that Google made about 15 percent less than a year earlier each time a user clicks on an online ad. That is the fourth straight quarter of erosion in Google's ad prices.
It is a warning sign for Facebook, which is trying to figure out how to make money off advertising on mobile devices.
Facebook stock declined 90 cents, or 4.6 percent, at $18.98, with most of the loss coming after Google's earnings report. The company went public in May at $38, but it has fallen as low as $17.55, in part because of investor concerns about ads.
"Google and Facebook are very reliant on online ads," said Scott Kessler, head of technology sector equity research at S&P Capital IQ, a research firm. "So if Google's results indicate a lack of demand and growth, that's obviously a worry for Facebook."
The broader market fared better: The Dow Jones industrial average closed down 8.06 points, or 0.06 percent, at 13,549.94. The Standard & Poor's 500 index fell 3.57 points, or 0.2 percent, to 1,457.34.
The broader market is "waiting for a clear catalyst," said Quincy Krosby, market strategist at Prudential Financial. What investors most want, she said, is a sense of direction about earnings and the economy.
"We basically know what happened in the last quarter," Krosby said. "What we're looking for is what's next: Are we turning a corner? Will demand pick up at the end of the year?"
Analysts expect S&P 500 companies to say that overall earnings shrank in the third quarter compared with a year ago, according to S&P Capital IQ. That would be the first drop in exactly three years.
American Express reported quarterly revenue late Wednesday that fell short of Wall Street's expectations even though earnings were in line. Amex said card holders' rate of spending has slowed in recent months. Its stock lost $1.76 to $57.61.
Strong profits for the insurer Travelers sent its stock up 3.6 percent. The company said claims from catastrophes plunged compared to the same quarter last year, which helped earnings double. Travelers' stock gained $2.56 to $73.94.
Weekly applications for unemployment benefits surged to a four-month high, a sharp rise from the previous week. The Labor Department pointed to technical reasons behind the swing, mainly delayed figures from one large state, California.
Better earnings from Johnson & Johnson and other companies, along with encouraging reports on industrial production and the housing market, have pushed the stock market higher this week. The Dow is up 1.6 percent and the S&P 500 is up 2 percent.
In other trading Thursday, the yield on the 10-year Treasury note was 1.83 percent, up from 1.82 percent Wednesday. The euro lost 0.4 cent against the dollar to $1.307. Crude oil fell 2 cents to $92.10 per barrel.
Among other stocks making big moves:
— EBay jumped $2.63, or 5.4 percent, to $50.83 after posting better net income and more revenue from its PayPal payments service and its online markets. The company also raised its full-year estimates for earnings and sales.
— Verizon Communications surged $1.06, or 2.4 percent, to $45.78. The company said its wireless division signed up more customers in the quarter. Verizon said its customers also added more devices to its Share Everything plan.