In a year that saw Big Law eagerly ship up to Boston, Washington, D.C.-based Arent Fox is arriving in Beantown in a merger with local, 55-lawyer Posternak Blankstein & Lund.

The merger, which the firms announced Tuesday, will officially go live Jan. 1, 2019, marking a major northeast expansion for Arent Fox and offering the latest evidence of Boston's hot legal market.

Still, Arent Fox firmwide managing partner Cristina Carvalho said the move was less about geography and more about the synergies between the two law firms.

“We weren't exactly looking at Boston specifically,” Carvalho said. “But Boston does meet our strategic goal of being in gateway cities with very strong practices where we excel in … in that respect Boston checks the box,” she added.

Founded in 1980 in Boston, Posternak specializes in business transactions and complex litigation. Carvalho noted that the firm, like Arent Fox, also has particular practice strength in real estate, finance and bankruptcy, as well as strong life sciences, intellectual property and biotech practices that are aligned with Boston's booming industries.

“We have similar cultures and similar philosophies and similar practice focus, so the combination of Arent Fox and Posternak made complete strategic sense for both firms,” Carvalho said.

With the merger, Arent Fox will now have more than 450 attorneys across its offices in Washington, D.C., Los Angeles, New York, San Francisco and Boston focusing on regulatory, transactional, intellectual property and litigation work.

Posternak managing partner Ira Deitsch, who joined the firm just after its founding nearly 40 years ago, will continue to lead the group as Boston managing partner with Arent Fox.

“Being a midsized firm, we don't have the breadth of practice or the number of people practicing in areas that Arent Fox has,” Deitsch said. ”For example, [we] have a lot of clients in life sciences, biotech [industries] who have needs that we can't serve from Boston.

If a client needed clearance from the Food and Drug Administration for a medical device, for example, Posternak couldn't provide FDA regulatory counsel from its singular office in Boston, Deitsch said. Arent Fox also has a broader IP platform that will let the office offer more support in patent and trademarks, he noted.

“We look at it as we're a smaller version of Arent Fox, and now we can become the bigger version that Arent Fox already is,” Deitsch said.

Arent Fox's entry into Boston caps a busy couple of years for the city's legal industry.

In May 2017, Kirkland & Ellis opened an office in the city's Bay Back neighborhood. Hogan Lovells followed, merging with local litigation boutique Collora while Womble Bond Dickinson opened its own office with a trio of McCarter & English IP partners. Earlier this year, Quinn Emanuel Urquhart & Sullivan opened an office in Boston with three of its IP litigators

The combination between Arent Fox and Posternak also helps cement 2018 as a record year for law firm combinations.

Through the third quarter of 2018, there have been 79 law firm tie-ups announced, according to data released by Altman Weil. So far, there have been 21 law firm mergers in the final quarter of 2018, according to Altman Weil's MergerLine tracker.

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