SEOUL - A South Korean company that said it had found a long-lost Russian “treasure ship”, causing a stock market flurry, apologised Thursday admitting it had not gleaned any riches from the wreck.

Start-up business Shinil Group announced last week it had discovered the imperial vessel Dmitri Donskoi off South Korea’s east coast, saying the ship was believed to contain gold bullion and coins worth $130 billion.

But financial regulators on Wednesday launched an investigation into the firm after news of the discovery caused the stock price of Jeil Steel - a company in which Shinil’s founder had acquired a large stake - to jump fivefold. Critics noted that in 2003 another firm had already sparked a stock bubble by announcing the discovery of the Donskoi, which sank in a 1905 naval battle against Japan. Shinil said it may have gone overboard on the claims and apologised for the “misunderstanding”, saying speculation on the value of treasure contained within the ship was based on news reports and unverified documents.

“We sincerely apologise to the people for this irresponsible citation,” said Choi Yong-seok, the firm’s CEO, bowing before TV cameras and photographers at a press conference.

Jeil Steel stock had hit 5,400 won ($4.82) but nosedived to around 1,785 won on Thursday, while Shinil replaced its board members and changed its name to Shinil Maritime Technology Co.

At the press conference, the company played a brief clip of underwater footage that appeared to show the ship, with the word “Donskoi” visible on the hull - but it stopped short of entering the wreck.

Observers have also questioned whether the claims were aimed at funnelling investment into a virtual currency which Shinil Group in Singapore had recently started to issue.

Choi insisted Shinil Group in Singapore had nothing to do with Shinil Group in Korea, although the two companies’ founders are siblings and Shinil Group in Singapore has been selling virtual coins, reportedly with a promise of handsome returns in case treasure is salvaged from the ship.

He also said Jeil Steel is not associated with Shinil although Shinil’s founder had acquired the stake in Jeil Steel before the discovery of the sunken ship.

Experts have said imperial Russia would have no reason to load vast treasure on a ship that was going into battle and have also noted that there was a safer land route to Vladivostok, the treasure’s supposed final destination.