A sign is posted on the exterior of Google headquarters on Jan. 30, 2014 in Mountain View, Calif.
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Google’s one-day rally is the biggest in history

Google share prices surged Friday a day after the company reported earnings, adding a total of $52 billion in market capitalization as of the start of trading, in the largest single-day gain ever, according to S&P Dow Jones Indices.

Google’s gain is having an outsized effect on the S&P 500 as well, adding 7 points at the open, according to Howard Silverblatt.

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The Internet giant beat analyst expectations in the earnings it reported after Thursday’s close, earning $6.99 per share on $17.83 in revenue.

Google trades under two tickers on the S&P 500, (GOOGL) and (GOOG). The former is the Class A shares, which enjoy voting rights, and the latter is the Class C shares, which don’t. Both classes separately feed into the S&P index.

Together, the gains in the two classes of Google shares add up to $52 billion worth of market cap, as of Friday’s first tick. That beats Apple’s April 2012 gain of $46.4 billion, the prior record holder for biggest increase in market cap.

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The stock’s gains actually intensified through the morning, with GOOGL surpassing $700 per share for the first time ever at 11:32 a.m. EDT.

However, the entirety of Google’s gain will not be reflected in the S&P 500, as not all of Google’s shares are freely floating (some are internally held). Google’s index float is 0.84, versus Apple’s float of 1. That means that only 84 percent of Google’s total gains are included in the float-weighted index.

Just how big are Google’s market cap gains in the context of the stock market as a whole?

“If that market wealth was put into the S&P 500 as a separate issue, it would be the 94th largest company in the S&P 500,” Silverblatt told CNBC in a phone interview.

This article first appeared at CNBC.com

Stock Market and Technology

Google's one-day rally is the biggest in history