It may seem like old news that Shearman & Sterling is opening an office in Houston. But the firm's announcement in early March that it had plans to enter the city came before a 90-day notice period ended for the Baker Botts partners who were leaving to start Shearman's new outpost.

With that window now closed, the partners have officially made the jump and concluded a waiting period that is rarely enforced within Big Law.

Two months after Shearman & Sterling moved into the Texas market with an office in Austin, the New York-based firm launched the Houston office on Thursday with six partners from three firms, along with six associates and more on the way.

Partners Hugh Tucker, Jeremy Kennedy and Coleson Bruce joined Shearman from Baker Botts, and Sarah McLean and Todd Lowther made a move from Thompson & Knight. Omar Samji will join soon from Jones Day.

Tucker, former chair of the oil and gas and projects practices at Baker Botts, will lead Shearman's Texas practice, and McLean, who does private equity transactions, will be deputy head.

Tucker, who practiced at Baker Botts for more than 35 years, said he is excited to join Shearman's global energy team, and also to have the challenge of growing an office in Houston. He said Shearman is a firm where the younger oil and gas lawyers he works with can build a practice and succeed.

Tucker said three of the six associates already working in the office came from Baker Botts and the other three were at Thompson & Knight. He said the firm will hire more associates in Houston.

Shearman confirmed months ago that it would open an office in Houston, but that opening was delayed by a 90-day hold Baker Botts put on its partners.

Baker Botts did not comment directly on hold, but the Houston-based firm said the movement of lawyers from firm to firm happens on a regular basis. “We are sorry to see these individuals leave, as they have been our friends, and we wish them every success in the future,” the firm said in a written statement, where it noted it has added 11 lateral partners over the last year.

Tucker said the 90-day hold was frustrating because the partners were anxious to get things rolling at Shearman. “It's one of those things that you wish you didn't have to go through, but I certainly understand the rationale for doing so,” he said, noting that firms do it “to try to solidify clients and to solidify personnel.”

He declined to identify clients he brought with him to Shearman.

David Beveridge, Shearman's senior partner, said despite the time it took for the Baker Botts team to be free to join the firm, “it all worked out fine.”

Thompson & Knight offered no comment regarding the lawyers who left the firm for Shearman. Samji, who is still at Jones Day, could not immediately be reached for comment.

Beveridge said Houston is an important location for the firm because it strengthens its energy practice.

“It's the energy capital of the world. We've put together a good team that covers the whole spectrum of oil and gas transactions,” he said, noting that the lawyers do upstream, midstream and downstream oil and gas transactions.

He said Shearman's goal is to have 50-to-60 lawyers based in Texas.

The lawyers in the Houston office will advise clients on M&A, divestitures, joint ventures and project work in the oil and gas sector. Tucker, Kennedy, Bruce and Samji do transactions for oil and gas companies, McLean focuses on private equity transactions and Lowther is a tax lawyer.

McLean and Bruce will split their time between Shearman's Austin and Houston offices.

The Austin office opened with eight lawyers who departed Andrews Kurth Keynon before its April 2 merger with Hunton & Williams. That Austin group focuses on advising emerging growth companies in the technology life sciences, and media and telecommunications industries.