SEOUL, April 27 (Reuters) – South Korea’s financial markets regulator said on Thursday it would strengthen its oversight of disclosures by listed companies on their business plans, citing a danger of speculative activity in their stocks.

The Financial Supervisory Service (FSS) said in a statement many companies announced plans to add popular sectors such as rechargeable batteries, artificial intelligence and robotics to their businesses but failed to disclose progress later.

The move came after stock prices of several companies making such announcements showed unusual rallies before crashing in a relatively short period and without any clear event.

It said it would strengthen its probes into stock price movements and transaction patterns for companies making such announcements and carry out swift investigations into suspicious cases for punishment.

If the regulator finds activity was fraudulent, it can refer cases to the prosecution office.

Reporting by Choonsik Yoo; Editing by Sonali Paul

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