Jeffrey C. Hammes, left, and Jon A. Ballis, right, of Kirkland & Ellis. (Courtesy photos)

Jeffrey Hammes’ reign as chairman of Kirkland & Ellis will come to an end in February 2020, closing what will be a 10-year tenure in which he oversaw one of the largest growth streaks in the history of American law firms.

Hammes will be replaced by Jon Ballis, a Chicago-based corporate partner who has become one of the firm’s best-known private equity lawyers.

“Jon is an incredible talent and has demonstrated the necessary leadership skills and business acumen to lead Kirkland & Ellis into the future,” Hammes said in a memo released to the firm and obtained by The American Lawyer.

The memo said Ballis will serve as “chairman-elect” until the transition in 2020, and that Hammes will remain a partner at the firm following the move out of leadership. The firm has a policy that requires members of its 15-member global management executive committee to step down in the fiscal year after they turn 60.

Kirkland’s revenue has nearly doubled during Hammes’ tenure, from $1.625 billion in fiscal 2010 to $3.165 billion last year, when it climbed to the very top of the Am Law 100. It has also become one of the wealthiest partnerships, with profits per equity partner rising more than 50 percent, from $3.1 million to $4.7 million.

Its head count in that span has grown by nearly 50 percent, from about 1,400 lawyers to nearly 2,000 as of last year. A firm spokeswoman said neither Hammes nor Ballis were available for interviews.

Ballis, a 1994 Harvard Law School graduate, joined Kirkland’s Chicago office, where the firm was founded and houses some 600-plus lawyers, in 2005 from crosstown rival Sidley Austin. He is a leader in the same private equity practice that Hammes was a part of before becoming a full-time leader of the business.

That practice has been a major component in the firm’s financial success. According to Mergermarket, which tracks private equity deals, Kirkland handled nearly twice as many private equity deals—1,184 from 2013 through this June. Latham & Watkins, the second largest law firm by revenue in the U.S., is the next closest with 609.

Hammes has also made a name for himself thanks to an aggressive style of lateral recruiting, paying top dollar to lure partners from New York’s elite lock-step firms. In one of the more recent examples, Kirkland reportedly agreed to pay former Cravath, Swaine & Moore partner Sandra Goldstein $11 million a year for five years.

While Goldstein is a top litigator, most of Kirkland’s big-ticket New York hires have been in the transactional space, where the firm has mostly focused its growth efforts under Hammes. He also focused on building the firm’s public M&A practice in New York by recruiting partners from Cravath, Skadden, Arps, Slate, Meagher & Flom and others.

Geographically, Kirkland has also focused on expanding in some of the highest-rate cities for legal services under Hammes’ watch, including London, San Francisco and Houston.

Kirkland’s fastest-growing offices include London, which has grown 61 percent since 2013, to 189 lawyers last year; New York, where head count is up 42 percent over the past five years, to 503 lawyers; San Francisco, up 36 percent since 2013, to 126 lawyers; and Houston, where the firm now has 107 lawyers since setting up shop in 2014.

“The competition among the top tier firms is fierce,” said Kay Hoppe, a Chicago-based legal recruiter. “Hammes did a great job of putting them at the top, and Ballis will do a great job of keeping them there.”

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