By Elizabeth Howcroft and David Gauthier-Villars

(Reuters) -While hosting the eldest son of U.S. President Donald Trump at a conference in Bulgaria on Sunday, crypto company Nexo Capital said it plans to return to the American market, two years after it paid a $45 million fine to settle U.S. regulatory charges.

Donald Trump Jr. was the star speaker in Sofia on Sunday at an event headlined "Trump Business Vision 2025" hosted by Nexo. Trump Jr., who has no official position in the U.S. government, was in the Bulgarian capital city as part of a tour across Eastern Europe.

Nexo's co-founder Antoni Trenchev told Reuters that the crypto firm plans to return to the U.S. in the coming months, and that it was having "constructive" conversations with regulators including the U.S. Securities and Exchange Commission (SEC), without giving further details.

The SEC declined to comment. Contacted through an aide, Trump Jr. did not respond to questions about Nexo.

In a statement released by Nexo on Monday, Trump Jr. said that crypto is "the future of finance."

"We see the opportunity for the financial sector and want to ensure we bring that back to the U.S.," he said.

Nexo co-founder Trenchev said that Trump Jr. was not helping the company to return to the U.S. but was “spreading the message that crypto is important to the United States and setting the stage.”

The Cayman Islands company had previously left the U.S. after disputes with regulators over a crypto lending product, which had resulted in Nexo agreeing in 2023 to pay $45 million in penalties to settle charges from the SEC and state regulators.

Nexo's planned re-entry comes as President Trump has heralded a major shift in government approach to the crypto industry.

The U.S. president, who courted crypto companies on the campaign trail, has called for easing crypto regulations and even launched his own cryptocurrency.

President Trump's embrace of cryptocurrencies represents a turnaround for the industry which came under scrutiny from regulators after a series of collapses at top crypto companies in 2022 exposed widespread misconduct and left millions of investors out of pocket.

Since Trump took office, the SEC has paused or dropped various pending lawsuits against crypto firms, and U.S. banking regulators have scrapped guidance warning banks to be cautious about crypto-related risks.

Trump handed over daily management of his multi-billion-dollar business portfolio to his children on entering the White House, but critics have raised concerns about potential conflicts of interest from the family's business ventures which include cryptocurrency and social media.

The Trump family is building its own crypto business, World Liberty Financial, which lists Donald Trump Jr. as an ambassador.

Trenchev, who previously served as a lawmaker in Bulgaria, said there had been a "tectonic shift" in U.S. attitudes towards crypto.

"It is more than just mere talk, there is actual work being done so that the United States does emerge as the place to be for crypto, and we are experiencing this first hand," Trenchev said. 

In a statement, Nexo described Sunday's invite-only event in Sofia as "a high-level dialogue on finance, technology, and the deepening alignment between American enterprise and international capital."

The conference featured speeches by Trump Jr. in his capacity as executive vice president of The Trump Organization, President Trump's family business, and Gila Gamliel, Israel's minister of innovation, science and technology.

Nexo's products include crypto-backed loans, crypto trading tools and a crypto exchange.

(Reporting by Elizabeth Howcroft in Paris and David Gauthier-Villars in Istanbul; additional reporting by Alexandra Ulmer in San Francisco, Editing by Louise Heavens)