UPDATE: 1/2/14, 11:33 p.m. EST. Wilson Sonsini’s role advising FireEye on its $1 billion buy of Mandiant has been added to the 21st paragraph of this story.

Mergers and acquisitions in the U.S. accounted for 43 percent of global deal volume in 2013, according to Thomson Reuters data analyzed by The New York Times’ DealBook, with the nation’s technology sector particularly active.

The DealBook story comes on the heels of a November report by the Silicon Valley Business Journal, which—citing quarterly data compiled by global accounting firm Ernst & Young—noted that the tech sector had seen more M&A activity since the beginning of 2013 than at any point starting with the so-called dotcom era more than a decade ago.

The industry continued its dealmaking run over the past week with a batch of transactions that totaled nearly $3 billion in value and yielded assignments for several Am Law 200 stalwarts.

In one of those deals, announced just before Christmas, enterprise software giant Oracle agreed to acquire business-to-consumer marketing software vendor Responsys for $1.39 billion. The deal, which is expected to close in the first half of this year, is the eighth acquisition announced by Oracle within the last year.

Redwood City, California–based Oracle, which is controlled by billionaire cofounder and CEO Lawrence Ellison (who saw his $77 million pay package rejected by shareholders in October), tapped Weil, Gotshal & Manges for counsel nearly a year ago for its $2.1 billion acquisition of network communications equipment company Acme Packet. Weil also advised Oracle in December 2012 on its $871 million buy of automated marketing software company Eloqua, according to our previous reports.

Keith Flaum—a Weil M&A partner who joined the firm’s Silicon Valley office in May 2012 with a group of transactional lawyers from the now-defunct Dewey & LeBoeuf—handled both of those deals for Oracle. And though the firm had advised the company on a variety of matters prior to the addition of the Dewey defectors, their arrival appears to have bolstered the relationship between the two.

Flaum and fellow M&A partner Richard “Rick” Climan, who led the Dewey team that decamped to Weil, are listed in an SEC filing as counsel to Oracle on its proposed acquisition of Responsys. Other Weil lawyers working on the matter for Oracle include tax partner Helyn Goldstein, employee benefits partner Amy Rubin and associates Cristiana Blauth Oliveira, Faraz Rana, Verity Rees and Gabriel Shapiro. (The Am Law Daily reported last week that Flaum had taken the lead for another Weil team advising Irish drug maker Jazz Pharmaceuticals on its $1 billion buy of Italian drug developer Gentium.)

Technology news website GigaOM reported earlier this year that Oracle—whose general counsel is Dorian Daley—is intent on fending off rivals on the way to snapping up automated software services companies in order to woo the chief marketing officers of its potential clients. When the company announced on Dec. 20 its plans to acquire Responsys—whose board has already approved the deal— Computerworld reported that the rationale for the transaction was to keep the target away from competitors.

Julian Ong, an Oakland native and veteran Silicon Valley in-house attorney who has served as general counsel for Responsys since 2010, told sibling publication The Recorder in 2012 that Fenwick & West and DLA Piper were the firms the company typically turns to for outside counsel.

It is Fenwick that has taken the lead for Responsys on the sale of the company to Oracle. Heading up the firm’s team on the matter are veteran Silicon Valley dealmaker and Fenwick corporate partner Gordon Davidson, securities and corporate finance cochair Jeffrey Vetter and private equity chair Scott Joachim.

In another tech sector deal announced in late December, Dealer.com, a private equity–owned provider of financial software to automobile dealers, announced that it is being acquired by Dealertrack Technologies for $1 billion.