Lotte Group Chairman Shin Dong-bin was invited to the White House on Monday by U.S. President Donald Trump eager to personally express appreciation after South Korea’s fifth-largest conglomerate opened a $3.1 billion ethane cracker and ethylene glycol production complex in the United States last week.

“They [Lotte] just invested $3.1 billion into Louisiana ? biggest investment in U.S. ever from a South Korean company, and thousands more jobs for Americans,” Trump tweeted, after his meeting with Shin, the first Korean business leader to privately meet with Trump at the White House. “Great partners like ROK [Republic of Korea] know the U.S. economy is running stronger than ever!” he added.

The meeting was also attended by Cho Yoon-je, Korea’s Ambassador to the U.S.; Kim Gyo-hyun, head of chemical business unit at Lotte Group; Yoon Jong-min, head of business strategy at Lotte Corp.; and Matthew Pottinger, senior director for Asian affairs in the U.S. National Security Council.

Shin was in the U.S. to attend a ceremony on Thursday for the opening of Lotte Chemical Corp.’s new ethylene production factory in Lake Charles, Louisiana. The company invested $3.1 billion to build the plant that is able to produce 1 million tons of ethylene and 700,000 tons of ethylene glycol per year. Ethylene is an essential material for petrochemical products such as plastic, rubber, and fiber. U.S. President Trump sent a letter through his deputy assistant Sylvia May Davis to congratulate the opening. Trump plans to visit Lake Charles on Tuesday, local time, and tour around liquefied natural gas export facilities before giving a speech on boosting economic growth and energy infrastructure.

At the meeting, Trump is known to have thanked Shin for the investment, saying Lotte Group did a good job in investing in Louisiana. Shin responded by saying that the investment progressed smoothly thanks to U.S. cooperation and hinted additional investment plans.

Cho, Korea’s Ambassador to the U.S., also told Trump that Korean companies are beefing up investment in the U.S. as of late and that of Korea’s total cumulative investment to the U.S., one fourth of the amount was carried out over the last two years under the Trump administration.

Shin, meanwhile, also shared with Trump Lotte Group’s business activities in the U.S., including of its investment in Lotte New York Palace Hotel. Trump responded by saying it was a good investment and asked the conglomerate to well preserve the time-honored building.

Lotte Group also said Trump and Shin also discussed ways to boost mutual cooperation to enhance bilateral ties. The meeting lasted for about 30 minutes.

Lotte Group’s $3.1 billion investment in the new petrochemical plant in Louisiana, meanwhile, is the second-largest single investment by a Korean conglomerate. Lotte invested 88 percent stake in the project.

Lotte Group plans to additionally produce 400,000 tons of ethylene at the facility after considering local conditions and also expand investment in hotel business.