Correction: Correction:

The tail sections of American Airlines (L) and US Airways aircraft February 14, 2013. AMR Corp and US Airways Group unveiled an $11 billion all-stock deal on that gives creditors of the bankrupt American Airlines parent control of the combined airline. (Mike Stone /Reuters)

Wall Street isn’t the only place buzzing about the recent merger announcements in the airline and office-supply industries.

The resurgence of the mega-merger is also putting K Street in the spotlight, especially the Washington lawyers at Dechert. The Philadelphia-based firm is representing US Airways in the proposed merger with American Airlines, and OfficeMax in the proposed merger with Office Depot.

Although it’s not unusual for the same group of lawyers to be involved in multiple large deals at the same time, it’s not every day those deals happen to be headline-grabbing mergers worth billions of dollars that have the potential to reshape their respective industries.

The American Airlines combination with smaller carrier US Airways, valued at about $11 billion, would create the nation’s largest airline. And Office Depot’s proposed acquisition of rival OfficeMax, an all-stock deal worth about $1.2 billion, would form the second-largest office-supply chain after Staples.

Dechert, a 138-year-old firm with about 900 lawyers in offices around the world, has a well­regarded antitrust practice among firms of its size. Dechert officials declined to comment for this story.

Leading the legal teams for both deals is veteran antitrust lawyer Paul T. Denis, who literally wrote the book on what are known as horizontal mergers, those involving firms in the same industry. While serving in the antitrust division of the Department of Justice — the agency that will review the airline merger — Denis helped author the set of guidelines that federal regulators turn to when considering mergers. While not legally binding, the rules known as the 1992 Horizontal Merger Guidelines are closely followed by both Justice and the Federal Trade Commission, which will review the Office Depot-OfficeMax deal.

Denis is no stranger to navigating deals that attract intense scrutiny from both regulators and the courts. He represented Medco Health Solutions in securing clearance for the company’s $29.1 billion merger with Express Scripts last year, which created the nation’s largest pharmacy benefits provider. It was the second-largest merger announced in 2011 after the ill-fated proposed combination of AT&T and T-Mobile.

Denis also defended Whole Foods Market in 2007 when the FTC challenged the grocery chain’s attempt to acquire Wild Oats Markets over concerns it would stifle competition. The contentious deal was approved by a federal court but the decision was later reversed; the supermarkets in 2009 reached a settlement in which Whole Foods agreed to sell three Wild Oats stores.

Antitrust experts say Denis’s strong track record could be a factor in the pending deals.

“The quality of the lawyering matters, so I’d say that is certainly a positive, helpful fact,” said Anthony Swisher of Squire Sanders, who represents corporations in Justice Department antitrust investigations. “Paul is a talented lawyer and will make the most of the facts he’s given, but at the end of the day, I think the facts control the outcome.”

For Dechert, handling two giant deals simultaneously will mean a huge influx of work. In the coming months, lawyers will have to pore over thousands of pages of data about the companies, examining their finances and market share and preparing to respond to requests for information should regulators launch a full investigation. Law firms often hire contract attorneys to help with such large matters.

“Anytime you’ve got multiple significant matters going, there are organizational challenges,” Swisher said. “There are resources challenges — making sure you have enough folks working on the matter to get done what needs to get done.”