JAKARTA (Reuters) - Goldman Sachs filed a $1 billion counter lawsuit on Tuesday against an Indonesian businessman who is seeking damages from the U.S. bank for conducting what he called “unlawful” trades in the shares of a property firm.

The logo of Goldman Sachs is displayed in their office located in Sydney, Australia, May 18, 2016. REUTERS/David Gray/File Photo

Benny Tjokrosaputro, president director of Indonesian property developer PT Hanson International Tbk MYRX.JK, filed a lawsuit in a Jakarta court in September against Goldman's unit, Goldman Sachs International.

Tjokrosaputro, who says that he owned the 425 million Hanson shares that Goldman traded, is seeking 15 trillion rupiah ($1.1 billion) in compensation from Goldman Sachs International and wants its assets frozen in Indonesia and overseas.

Citibank, a custodian bank for Goldman Sachs International, was named as a co-defendant in his lawsuit.

Goldman had said in response that Goldman Sachs International had bought the Hanson shares from New York hedge fund Platinum Partners in a series of “valid” transactions on the Indonesia Stock Exchange (IDX) between February 2015 and March 2016.

Top executives of Platinum Partners were arrested in December and charged with running a $1 billion fraud. Platinum has declined to comment on the legal dispute between Tjokrosaputro and Goldman.

Goldman filed the counterclaim against Tjokrosaputro for “the reputational damage and negative business impact” that Tjokrosaputro’s actions had caused, it said in a statement on Tuesday. It said Tjokrosaputro’s actions had caused it “at least 15 trillion rupiah in immaterial damages”.

In June last year, Tjokrosaputro had lodged a complaint to the Jakarta police alleging that the Hanson shares had been “fraudulently embezzled” from him, according to Goldman’s counterclaim documents.

Tjokrosaputro had also put out newspaper advertisements that damaged Goldman’s reputation, according to the documents.

“Potential clients that could have wanted to do a transaction or conduct a business relationship with our client might have held themselves back as a result,” Harjon Sinaga, a lawyer representing Goldman, told reporters after he filed the counterclaim in a Jakarta court.

Tjokrosaputro declined to comment when contacted by phone. His lawyer, Nadia Saphira Ganie, also declined to comment, saying the team needed to study the counterclaim by Goldman.

“INVESTOR CONFIDENCE”

Goldman has said the legal dispute may affect foreign investor sentiment toward Southeast Asia’s biggest economy.

The bank's comments came after Indonesia's government recently raised investor concerns by cutting business ties with JPMorgan Chase & Co JPM.N over a negative research report and partially reversing a mining policy.

“If the challenge made against Goldman Sachs’ trades by Mr. Tjokrosaputro in the South Jakarta District Court is upheld, investor confidence in all trades by all investors crossing the IDX could be eroded,” Goldman said in the statement.

Tito Sulistio, the president director of the IDX, told Reuters that “at the moment, it’s a matter for the shareholders to resolve”.

The IDX will only do a review when there is an official complaint to the bourse or if the development affects share prices in the market, Sulistio added.

Hanson shares were up 4.5 percent on Tuesday after closing 1.9 percent lower on Monday. As of Jan. 12, Tjokrosaputro owned a 10.21 percent stake in Hanson, according to Thomson Reuters data.