Google's

response has been added to this story.

MOUNTAIN VIEW, Calif. (

TheStreet

) --

Google

(GOOG) - Get Report

shares slumped on Tuesday amid ongoing chatter about a possible

acquisition of online discounter Groupon

and

an impending EU antitrust probe.

The search giant's shares closed down $26.4, or 4.54%, at $555.71 on Tuesday, far outpacing the broader retreat in tech stocks that saw the Nasdaq slip 1.07%. Shares of search sector rivals

Yahoo

(YHOO)

and

Microsoft

(MSFT) - Get Report

also closed down, falling 3.45% and 0.21%, respectively.

Citing sources close to the situation, the

Wall Street Journal

blog

All Things Digital

reported that Google has offered $5.3 billion for Groupon, in what would be the search giant's biggest-ever acquisition.

The

New York Times

, also citing people with direct knowledge of the matter, reports Google could acquire Groupon for between $5 billion to $6 billion.

Amid the chatter, some investors and analysts have expressed worries about spending a record amount of capital for a startup that may not fit into Google's corporate culture, while others have applauded the deal, noting that Groupon could serve as a springboard for Google into local advertising.

Google, however, declined to provide comment for this story when contacted by

TheStreet

. "We don't comment on rumor or speculation," explained a Google spokesman, in an email.

--Written by James Rogers in New York.

>To follow the writer on Twitter, go to

http://twitter.com/jamesjrogers

.

>To submit a news tip, send an email to:

tips@thestreet.com