Simpson Thacher & Bartlett has announced plans to open an office in Seoul, reports The Asian Lawyer.

The US firm said in a statement that it will open in the South Korean capital "as soon as practicable in 2012." The announcement follows the ratification of a trade deal between the US and Korea, the passage of which opens the way for US firms to apply to enter Korea's legal market as of this month.

New York partner Youngjin Sohn will relocate to Seoul to lead the new base, along with several associates from the firm's Hong Kong office.

Korea will be the fourth Asian location for Simpson Thacher, which already has offices in Hong Kong, Beijing, and Tokyo. The firm is among the market leaders for Korea work, and has recently acted on deals such as the initial public offerings of Samsung Life Insurance and Korea Life Insurance  in 2010, raising $4.4bn (£2.8bn) and $1.6bn (£1bn) resepectively.

In the wake of the trade deal, a raft of US firms have announced their intention to launch in Korea, including Cleary Gottlieb Steen & Hamilton, which announced last month it will open an office in Seoul, with Sheppard Mullin Richter & Hampton following suit shortly afterwards.

Paul Hastings has also said it wants to be among the first firms to enter the Korea market, while McDermott Will & Emery and Ropes & Gray have also said they are considering opening offices in Korea.

UK firms are also allowed to open offices in Korea following the passage of a free trade agreement between the EU and Korea in July.

Last year Clifford Chance confirmed that it is planning to open in the country once the market is liberalised, with other firms including DLA Piper and Allen & Overy in earlier stages of evaluating the market.

The Asian Lawyer is a US affiliate title of Legal Week.

For more, see First into Seoul? No thanks – many firms reluctant to launch in the local Korean market.